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前言 {#%E5%89%8D%E8%A8%80}
本教程基于群晖的NAS设备DS423+ 的docker功能进行搭建，DSM版本为 7.2.1-69057 Update 5。
简介 {#%E7%AE%80%E4%BB%8B}
Redis（Remote Dictionary Server，远程字典服务器）是一个开源的内存中数据结构存储系统，通常用作数据库、缓存和消息代理。它支持多种类型的数据结构，如字符串（strings）、列表（lists）、集合（sets）、有序集合（sorted sets）、散列（hashes）、位图（bitmaps）、超日志（hyperloglogs）和地理空间（geospatial）索引半径查询。
以下是 Redis 的一些关键特性：
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内存中存储：Redis 把所有数据都存储在内存中，这使得读写操作非常快速。
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持久化：尽管 Redis 是一个内存中的数据存储系统，但它提供了持久化功能，可以将内存中的数据保存到磁盘，防止数据丢失。
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支持事务：Redis 支持简单的事务功能，可以保证操作的原子性。
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丰富的数据类型：Redis 提供了丰富的数据类型操作，可以很容易地实现计数器、实时分析、会话缓存等功能。
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发布/订阅功能：Redis 支持发布订阅模式，可以作为消息系统使用。
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主从复制：Redis 支持主从复制，可以进行读写分离，提高系统的可用性和伸缩性。
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哨兵系统：Redis Sentinel 系统用于监控 Redis 主服务器的性能和健康状态，可以在主服务器故障时自动进行故障转移。
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集群：Redis Cluster 是 Redis 的分布式实现，可以自动分割数据到多个节点，提供自动分区和复制。
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高可用性：通过 Redis Sentinel 和 Redis Cluster，Redis 可以构建高可用性的系统。
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支持 Lua 脚本：Redis 支持使用 Lua 语言编写脚本，可以在服务器端执行复杂的操作。
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客户端库：Redis 拥有丰富的客户端库，支持多种编程语言，如 Python、Java、C#、Node.js 等。
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灵活的配置：Redis 提供了大量的配置选项，可以根据需要调整性能和资源使用。
Redis 广泛用于提高应用程序的性能，通过缓存常用数据减少对磁盘数据库的访问，同时也用于实现复杂的数据结构和操作，以支持各种应用程序的需求。
部署 {#%E9%83%A8%E7%BD%B2}
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在群晖NAS上面的"File Station"中新建一个docker映射文件，用于映射docker中redis的数据。
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在自己电脑上新建一个文件，命名为
redis.conf，然后将以下配置复制粘贴进去并保存。# Redis configuration file example. Note that in order to read the configuration file, Redis must be ================================================================ started with the file path as first argument: ============================================= ./redis-server /path/to/redis.conf ================================== Note on units: when memory size is needed, it is possible to specify ==================================================================== it in the usual form of 1k 5GB 4M and so forth: =============================================== 1k =\> 1000 bytes ================= 1kb =\> 1024 bytes ================== 1m =\> 1000000 bytes ==================== 1mb =\> 1024\*1024 bytes ======================== 1g =\> 1000000000 bytes ======================= 1gb =\> 1024*1024*1024 bytes ============================ units are case insensitive so 1GB 1Gb 1gB are all the same. =========================================================== ################################## INCLUDES ################################### Include one or more other config files here. This is useful if you ================================================================== have a standard template that goes to all Redis servers but also need ===================================================================== to customize a few per-server settings. Include files can include ================================================================= other files, so use this wisely. ================================ Note that option "include" won't be rewritten by command "CONFIG REWRITE" ========================================================================= from admin or Redis Sentinel. Since Redis always uses the last processed ======================================================================== line as value of a configuration directive, you'd better put includes ===================================================================== at the beginning of this file to avoid overwriting config change at runtime. ============================================================================ If instead you are interested in using includes to override configuration ========================================================================= options, it is better to use include as the last line. ====================================================== Included paths may contain wildcards. All files matching the wildcards will =========================================================================== be included in alphabetical order. ================================== Note that if an include path contains a wildcards but no files match it when ============================================================================ the server is started, the include statement will be ignored and no error will ============================================================================== be emitted. It is safe, therefore, to include wildcard files from empty ======================================================================= directories. ============ include /path/to/local.conf =========================== include /path/to/other.conf =========================== include /path/to/fragments/\*.conf ================================== ################################## MODULES ##################################### Load modules at startup. If the server is not able to load modules ================================================================== it will abort. It is possible to use multiple loadmodule directives. ==================================================================== loadmodule /path/to/my_module.so ================================ loadmodule /path/to/other_module.so =================================== ################################## NETWORK ##################################### By default, if no "bind" configuration directive is specified, Redis listens ============================================================================ for connections from all available network interfaces on the host machine. ========================================================================== It is possible to listen to just one or multiple selected interfaces using ========================================================================== the "bind" configuration directive, followed by one or more IP addresses. ========================================================================= Each address can be prefixed by "-", which means that redis will not fail to ============================================================================ start if the address is not available. Being not available only refers to ========================================================================= addresses that does not correspond to any network interface. Addresses that =========================================================================== are already in use will always fail, and unsupported protocols will always BE ============================================================================= silently skipped. ================= Examples: ========= bind 192.168.1.100 10.0.0.1 # listens on two specific IPv4 addresses ==================================================================== bind 127.0.0.1 ::1 # listens on loopback IPv4 and IPv6 ====================================================== bind \* -::\* # like the default, all available interfaces ========================================================== \~\~\~ WARNING \~\~\~ If the computer running Redis is directly exposed to the ============================================================================== internet, binding to all the interfaces is dangerous and will expose the ======================================================================== instance to everybody on the internet. So by default we uncomment the ===================================================================== following bind directive, that will force Redis to listen only on the ===================================================================== IPv4 and IPv6 (if available) loopback interface addresses (this means Redis =========================================================================== will only be able to accept client connections from the same host that it is ============================================================================ running on). ============ IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES ====================================================================== COMMENT OUT THE FOLLOWING LINE. =============================== You will also need to set a password unless you explicitly disable protected ============================================================================ mode. ===== \~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~\~ ================================================================================================================================================ bind 0.0.0.0 By default, outgoing connections (from replica to master, from Sentinel to ========================================================================== instances, cluster bus, etc.) are not bound to a specific local address. In =========================================================================== most cases, this means the operating system will handle that based on routing ============================================================================= and the interface through which the connection goes out. ======================================================== Using bind-source-addr it is possible to configure a specific address to bind ============================================================================= to, which may also affect how the connection gets routed. ========================================================= Example: ======== bind-source-addr 10.0.0.1 ========================= Protected mode is a layer of security protection, in order to avoid that ======================================================================== Redis instances left open on the internet are accessed and exploited. ===================================================================== When protected mode is on and the default user has no password, the server ========================================================================== only accepts local connections from the IPv4 address (127.0.0.1), IPv6 address ============================================================================== (::1) or Unix domain sockets. ============================= By default protected mode is enabled. You should disable it only if =================================================================== you are sure you want clients from other hosts to connect to Redis ================================================================== even if no authentication is configured. ======================================== protected-mode yes Redis uses default hardened security configuration directives to reduce the =========================================================================== attack surface on innocent users. Therefore, several sensitive configuration ============================================================================ directives are immutable, and some potentially-dangerous commands are blocked. ============================================================================== Configuration directives that control files that Redis writes to (e.g., 'dir' ============================================================================= and 'dbfilename') and that aren't usually modified during runtime ================================================================= are protected by making them immutable. ======================================= Commands that can increase the attack surface of Redis and that aren't usually ============================================================================== called by users are blocked by default. ======================================= These can be exposed to either all connections or just local ones by setting ============================================================================ each of the configs listed below to either of these values: =========================================================== no - Block for any connection (remain immutable) ================================================ yes - Allow for any connection (no protection) ============================================== local - Allow only for local connections. Ones originating from the =================================================================== IPv4 address (127.0.0.1), IPv6 address (::1) or Unix domain sockets. ==================================================================== enable-protected-configs no =========================== enable-debug-command no ======================= enable-module-command no ======================== Accept connections on the specified port, default is 6379 (IANA #815344). ========================================================================= If port 0 is specified Redis will not listen on a TCP socket. ============================================================= port 6379 TCP listen() backlog. ===================== In high requests-per-second environments you need a high backlog in order ========================================================================= to avoid slow clients connection issues. Note that the Linux kernel =================================================================== will silently truncate it to the value of /proc/sys/net/core/somaxconn so ========================================================================= make sure to raise both the value of somaxconn and tcp_max_syn_backlog ====================================================================== in order to get the desired effect. =================================== tcp-backlog 511 Unix socket. ============ Specify the path for the Unix socket that will be used to listen for ==================================================================== incoming connections. There is no default, so Redis will not listen =================================================================== on a unix socket when not specified. ==================================== unixsocket /run/redis.sock ========================== unixsocketperm 700 ================== Close the connection after a client is idle for N seconds (0 to disable) ======================================================================== timeout 0 TCP keepalive. ============== If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence ==================================================================== of communication. This is useful for two reasons: ================================================= 1) Detect dead peers. ===================== 2) Force network equipment in the middle to consider the connection to be ========================================================================= alive. ====== On Linux, the specified value (in seconds) is the period used to send ACKs. =========================================================================== Note that to close the connection the double of the time is needed. =================================================================== On other kernels the period depends on the kernel configuration. ================================================================ A reasonable value for this option is 300 seconds, which is the new =================================================================== Redis default starting with Redis 3.2.1. ======================================== tcp-keepalive 300 Apply OS-specific mechanism to mark the listening socket with the specified =========================================================================== ID, to support advanced routing and filtering capabilities. =========================================================== On Linux, the ID represents a connection mark. ============================================== On FreeBSD, the ID represents a socket cookie ID. ================================================= On OpenBSD, the ID represents a route table ID. =============================================== The default value is 0, which implies no marking is required. ============================================================= socket-mark-id 0 ================ ################################# TLS/SSL ##################################### By default, TLS/SSL is disabled. To enable it, the "tls-port" configuration =========================================================================== directive can be used to define TLS-listening ports. To enable TLS on the ========================================================================= default port, use: ================== port 0 ====== tls-port 6379 ============= Configure a X.509 certificate and private key to use for authenticating the =========================================================================== server to connected clients, masters or cluster peers. These files should be ============================================================================ PEM formatted. ============== tls-cert-file redis.crt ======================= tls-key-file redis.key ====================== If the key file is encrypted using a passphrase, it can be included here ======================================================================== as well. ======== tls-key-file-pass secret ======================== Normally Redis uses the same certificate for both server functions (accepting ============================================================================= connections) and client functions (replicating from a master, establishing ========================================================================== cluster bus connections, etc.). =============================== Sometimes certificates are issued with attributes that designate them as ======================================================================== client-only or server-only certificates. In that case it may be desired to use ============================================================================== different certificates for incoming (server) and outgoing (client) ================================================================== connections. To do that, use the following directives: ====================================================== tls-client-cert-file client.crt =============================== tls-client-key-file client.key ============================== If the key file is encrypted using a passphrase, it can be included here ======================================================================== as well. ======== tls-client-key-file-pass secret =============================== Configure a DH parameters file to enable Diffie-Hellman (DH) key exchange, ========================================================================== required by older versions of OpenSSL (\<3.0). Newer versions do not require ============================================================================ this configuration and recommend against it. ============================================ tls-dh-params-file redis.dh =========================== Configure a CA certificate(s) bundle or directory to authenticate TLS/SSL ========================================================================= clients and peers. Redis requires an explicit configuration of at least one =========================================================================== of these, and will not implicitly use the system wide configuration. ==================================================================== tls-ca-cert-file ca.crt ======================= tls-ca-cert-dir /etc/ssl/certs ============================== By default, clients (including replica servers) on a TLS port are required ========================================================================== to authenticate using valid client side certificates. ===================================================== If "no" is specified, client certificates are not required and not accepted. ============================================================================ If "optional" is specified, client certificates are accepted and must be ======================================================================== valid if provided, but are not required. ======================================== tls-auth-clients no =================== tls-auth-clients optional ========================= By default, a Redis replica does not attempt to establish a TLS connection ========================================================================== with its master. ================ Use the following directive to enable TLS on replication links. =============================================================== tls-replication yes =================== By default, the Redis Cluster bus uses a plain TCP connection. To enable ======================================================================== TLS for the bus protocol, use the following directive: ====================================================== tls-cluster yes =============== By default, only TLSv1.2 and TLSv1.3 are enabled and it is highly recommended ============================================================================= that older formally deprecated versions are kept disabled to reduce the attack surface. ======================================================================================= You can explicitly specify TLS versions to support. =================================================== Allowed values are case insensitive and include "TLSv1", "TLSv1.1", "TLSv1.2", ============================================================================== "TLSv1.3" (OpenSSL \>= 1.1.1) or any combination. ================================================= To enable only TLSv1.2 and TLSv1.3, use: ======================================== tls-protocols "TLSv1.2 TLSv1.3" =============================== Configure allowed ciphers. See the ciphers(1ssl) manpage for more information ============================================================================= about the syntax of this string. ================================ Note: this configuration applies only to \<= TLSv1.2. ===================================================== tls-ciphers DEFAULT:!MEDIUM =========================== Configure allowed TLSv1.3 ciphersuites. See the ciphers(1ssl) manpage for more ============================================================================== information about the syntax of this string, and specifically for TLSv1.3 ========================================================================= ciphersuites. ============= tls-ciphersuites TLS_CHACHA20_POLY1305_SHA256 ============================================= When choosing a cipher, use the server's preference instead of the client ========================================================================= preference. By default, the server follows the client's preference. =================================================================== tls-prefer-server-ciphers yes ============================= By default, TLS session caching is enabled to allow faster and less expensive ============================================================================= reconnections by clients that support it. Use the following directive to disable ================================================================================ caching. ======== tls-session-caching no ====================== Change the default number of TLS sessions cached. A zero value sets the cache ============================================================================= to unlimited size. The default size is 20480. ============================================= tls-session-cache-size 5000 =========================== Change the default timeout of cached TLS sessions. The default timeout is 300 ============================================================================= seconds. ======== tls-session-cache-timeout 60 ============================ ################################# GENERAL ##################################### By default Redis does not run as a daemon. Use 'yes' if you need it. ==================================================================== Note that Redis will write a pid file in /var/run/redis.pid when daemonized. ============================================================================ When Redis is supervised by upstart or systemd, this parameter has no impact. ============================================================================= daemonize no If you run Redis from upstart or systemd, Redis can interact with your ====================================================================== supervision tree. Options: ========================== supervised no - no supervision interaction ========================================== supervised upstart - signal upstart by putting Redis into SIGSTOP mode ====================================================================== requires "expect stop" in your upstart job config ================================================= supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET ======================================================================== on startup, and updating Redis status on a regular ================================================== basis. ====== supervised auto - detect upstart or systemd method based on =========================================================== UPSTART_JOB or NOTIFY_SOCKET environment variables ================================================== Note: these supervision methods only signal "process is ready." =============================================================== They do not enable continuous pings back to your supervisor. ============================================================ The default is "no". To run under upstart/systemd, you can simply uncomment =========================================================================== the line below: =============== supervised auto =============== If a pid file is specified, Redis writes it where specified at startup ====================================================================== and removes it at exit. ======================= When the server runs non daemonized, no pid file is created if none is ====================================================================== specified in the configuration. When the server is daemonized, the pid file =========================================================================== is used even if not specified, defaulting to "/var/run/redis.pid". ================================================================== Creating a pid file is best effort: if Redis is not able to create it ===================================================================== nothing bad happens, the server will start and run normally. ============================================================ Note that on modern Linux systems "/run/redis.pid" is more conforming ===================================================================== and should be used instead. =========================== pidfile /var/run/redis_6379.pid Specify the server verbosity level. =================================== This can be one of: =================== debug (a lot of information, useful for development/testing) ============================================================ verbose (many rarely useful info, but not a mess like the debug level) ====================================================================== notice (moderately verbose, what you want in production probably) ================================================================= warning (only very important / critical messages are logged) ============================================================ loglevel notice Specify the log file name. Also the empty string can be used to force ===================================================================== Redis to log on the standard output. Note that if you use standard ================================================================== output for logging but daemonize, logs will be sent to /dev/null ================================================================ logfile "" To enable logging to the system logger, just set 'syslog-enabled' to yes, ========================================================================= and optionally update the other syslog parameters to suit your needs. ===================================================================== syslog-enabled no ================= Specify the syslog identity. ============================ syslog-ident redis ================== Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7. =================================================================== syslog-facility local0 ====================== To disable the built in crash log, which will possibly produce cleaner core =========================================================================== dumps when they are needed, uncomment the following: ==================================================== crash-log-enabled no ==================== To disable the fast memory check that's run as part of the crash log, which =========================================================================== will possibly let redis terminate sooner, uncomment the following: ================================================================== crash-memcheck-enabled no ========================= Set the number of databases. The default database is DB 0, you can select ========================================================================= a different one on a per-connection basis using SELECT \<dbid\> where ===================================================================== dbid is a number between 0 and 'databases'-1 ============================================ databases 16 By default Redis shows an ASCII art logo only when started to log to the ======================================================================== standard output and if the standard output is a TTY and syslog logging is ========================================================================= disabled. Basically this means that normally a logo is displayed only in ======================================================================== interactive sessions. ===================== However it is possible to force the pre-4.0 behavior and always show a ====================================================================== ASCII art logo in startup logs by setting the following option to yes. ====================================================================== always-show-logo no By default, Redis modifies the process title (as seen in 'top' and 'ps') to =========================================================================== provide some runtime information. It is possible to disable this and leave ========================================================================== the process name as executed by setting the following to no. ============================================================ set-proc-title yes When changing the process title, Redis uses the following template to construct =============================================================================== the modified title. =================== Template variables are specified in curly brackets. The following variables are =============================================================================== supported: ========== {title} Name of process as executed if parent, or type of child process. ======================================================================== {listen-addr} Bind address or '\*' followed by TCP or TLS port listening on, or =============================================================================== Unix socket if only that's available. ===================================== {server-mode} Special mode, i.e. "\[sentinel\]" or "\[cluster\]". ================================================================= {port} TCP port listening on, or 0. =================================== {tls-port} TLS port listening on, or 0. ======================================= {unixsocket} Unix domain socket listening on, or "". ==================================================== {config-file} Name of configuration file used. ============================================== proc-title-template "{title} {listen-addr} {server-mode}" ################################ SNAPSHOTTING ################################ Save the DB to disk. ==================== save \<seconds\> \<changes\> \[\<seconds\> \<changes\> ...\] ============================================================ Redis will save the DB if the given number of seconds elapsed and it ==================================================================== surpassed the given number of write operations against the DB. ============================================================== Snapshotting can be completely disabled with a single empty string argument =========================================================================== as in following example: ======================== save "" ======= Unless specified otherwise, by default Redis will save the DB: ============================================================== \* After 3600 seconds (an hour) if at least 1 change was performed ================================================================== \* After 300 seconds (5 minutes) if at least 100 changes were performed ======================================================================= \* After 60 seconds if at least 10000 changes were performed ============================================================ You can set these explicitly by uncommenting the following line. ================================================================ save 3600 1 300 100 60 10000 ============================ By default Redis will stop accepting writes if RDB snapshots are enabled ======================================================================== (at least one save point) and the latest background save failed. ================================================================ This will make the user aware (in a hard way) that data is not persisting ========================================================================= on disk properly, otherwise chances are that no one will notice and some ======================================================================== disaster will happen. ===================== If the background saving process will start working again Redis will ==================================================================== automatically allow writes again. ================================= However if you have setup your proper monitoring of the Redis server ==================================================================== and persistence, you may want to disable this feature so that Redis will ======================================================================== continue to work as usual even if there are problems with disk, =============================================================== permissions, and so forth. ========================== stop-writes-on-bgsave-error yes Compress string objects using LZF when dump .rdb databases? =========================================================== By default compression is enabled as it's almost always a win. ============================================================== If you want to save some CPU in the saving child set it to 'no' but =================================================================== the dataset will likely be bigger if you have compressible values or keys. ========================================================================== rdbcompression yes Since version 5 of RDB a CRC64 checksum is placed at the end of the file. ========================================================================= This makes the format more resistant to corruption but there is a performance ============================================================================= hit to pay (around 10%) when saving and loading RDB files, so you can disable it ================================================================================ for maximum performances. ========================= RDB files created with checksum disabled have a checksum of zero that will ========================================================================== tell the loading code to skip the check. ======================================== rdbchecksum yes Enables or disables full sanitization checks for ziplist and listpack etc when ============================================================================== loading an RDB or RESTORE payload. This reduces the chances of a assertion or ============================================================================= crash later on while processing commands. ========================================= Options: ======== no - Never perform full sanitization ==================================== yes - Always perform full sanitization ====================================== clients - Perform full sanitization only for user connections. ============================================================== Excludes: RDB files, RESTORE commands received from the master ============================================================== connection, and client connections which have the ================================================= skip-sanitize-payload ACL flag. =============================== The default should be 'clients' but since it currently affects cluster ====================================================================== resharding via MIGRATE, it is temporarily set to 'no' by default. ================================================================= sanitize-dump-payload no ======================== The filename where to dump the DB ================================= dbfilename dump.rdb Remove RDB files used by replication in instances without persistence ===================================================================== enabled. By default this option is disabled, however there are environments =========================================================================== where for regulations or other security concerns, RDB files persisted on ======================================================================== disk by masters in order to feed replicas, or stored on disk by replicas ======================================================================== in order to load them for the initial synchronization, should be deleted ======================================================================== ASAP. Note that this option ONLY WORKS in instances that have both AOF ====================================================================== and RDB persistence disabled, otherwise is completely ignored. ============================================================== An alternative (and sometimes better) way to obtain the same effect is ====================================================================== to use diskless replication on both master and replicas instances. However ========================================================================== in the case of replicas, diskless is not always an option. ========================================================== rdb-del-sync-files no The working directory. ====================== The DB will be written inside this directory, with the filename specified ========================================================================= above using the 'dbfilename' configuration directive. ===================================================== The Append Only File will also be created inside this directory. ================================================================ Note that you must specify a directory here, not a file name. ============================================================= dir ./ ################################# REPLICATION ################################# Master-Replica replication. Use replicaof to make a Redis instance a copy of ============================================================================ another Redis server. A few things to understand ASAP about Redis replication. ============================================================================== +------------------+ +---------------+ ====================================== \| Master \| ---\> \| Replica \| ================================ \| (receive writes) \| \| (exact copy) \| ========================================= +------------------+ +---------------+ ====================================== 1) Redis replication is asynchronous, but you can configure a master to ======================================================================= stop accepting writes if it appears to be not connected with at least ===================================================================== a given number of replicas. =========================== 2) Redis replicas are able to perform a partial resynchronization with the ========================================================================== master if the replication link is lost for a relatively small amount of ======================================================================= time. You may want to configure the replication backlog size (see the next ========================================================================== sections of this file) with a sensible value depending on your needs. ===================================================================== 3) Replication is automatic and does not need user intervention. After a ======================================================================== network partition replicas automatically try to reconnect to masters ==================================================================== and resynchronize with them. ============================ replicaof \<masterip\> \<masterport\> ===================================== If the master is password protected (using the "requirepass" configuration ========================================================================== directive below) it is possible to tell the replica to authenticate before ========================================================================== starting the replication synchronization process, otherwise the master will =========================================================================== refuse the replica request. =========================== masterauth \<master-password\> ============================== However this is not enough if you are using Redis ACLs (for Redis version ========================================================================= 6 or greater), and the default user is not capable of running the PSYNC ======================================================================= command and/or other commands needed for replication. In this case it's ======================================================================= better to configure a special user to use with replication, and specify the =========================================================================== masteruser configuration as such: ================================= masteruser \<username\> ======================= When masteruser is specified, the replica will authenticate against its ======================================================================= master using the new AUTH form: AUTH \<username\> \<password\>. =============================================================== When a replica loses its connection with the master, or when the replication ============================================================================ is still in progress, the replica can act in two different ways: ================================================================ 1) if replica-serve-stale-data is set to 'yes' (the default) the replica will ============================================================================= still reply to client requests, possibly with out of date data, or the ====================================================================== data set may just be empty if this is the first synchronization. ================================================================ 2) If replica-serve-stale-data is set to 'no' the replica will reply with error =============================================================================== "MASTERDOWN Link with MASTER is down and replica-serve-stale-data is set to 'no'" ================================================================================= to all data access commands, excluding commands such as: ======================================================== INFO, REPLICAOF, AUTH, SHUTDOWN, REPLCONF, ROLE, CONFIG, SUBSCRIBE, =================================================================== UNSUBSCRIBE, PSUBSCRIBE, PUNSUBSCRIBE, PUBLISH, PUBSUB, COMMAND, POST, ====================================================================== HOST and LATENCY. ================= replica-serve-stale-data yes You can configure a replica instance to accept writes or not. Writing against ============================================================================= a replica instance may be useful to store some ephemeral data (because data =========================================================================== written on a replica will be easily deleted after resync with the master) but ============================================================================= may also cause problems if clients are writing to it because of a ================================================================= misconfiguration. ================= Since Redis 2.6 by default replicas are read-only. ================================================== Note: read only replicas are not designed to be exposed to untrusted clients ============================================================================ on the internet. It's just a protection layer against misuse of the instance. ============================================================================= Still a read only replica exports by default all the administrative commands ============================================================================ such as CONFIG, DEBUG, and so forth. To a limited extent you can improve ======================================================================== security of read only replicas using 'rename-command' to shadow all the ======================================================================= administrative / dangerous commands. ==================================== replica-read-only yes Replication SYNC strategy: disk or socket. ========================================== New replicas and reconnecting replicas that are not able to continue the ======================================================================== replication process just receiving differences, need to do what is called a =========================================================================== "full synchronization". An RDB file is transmitted from the master to the ========================================================================= replicas. ========= The transmission can happen in two different ways: ================================================== 1) Disk-backed: The Redis master creates a new process that writes the RDB ========================================================================== file on disk. Later the file is transferred by the parent ========================================================= process to the replicas incrementally. ====================================== 2) Diskless: The Redis master creates a new process that directly writes the ============================================================================ RDB file to replica sockets, without touching the disk at all. ============================================================== With disk-backed replication, while the RDB file is generated, more replicas ============================================================================ can be queued and served with the RDB file as soon as the current child ======================================================================= producing the RDB file finishes its work. With diskless replication instead =========================================================================== once the transfer starts, new replicas arriving will be queued and a new ======================================================================== transfer will start when the current one terminates. ==================================================== When diskless replication is used, the master waits a configurable amount of ============================================================================ time (in seconds) before starting the transfer in the hope that multiple ======================================================================== replicas will arrive and the transfer can be parallelized. ========================================================== With slow disks and fast (large bandwidth) networks, diskless replication ========================================================================= works better. ============= repl-diskless-sync yes When diskless replication is enabled, it is possible to configure the delay =========================================================================== the server waits in order to spawn the child that transfers the RDB via socket ============================================================================== to the replicas. ================ This is important since once the transfer starts, it is not possible to serve ============================================================================= new replicas arriving, that will be queued for the next RDB transfer, so the ============================================================================ server waits a delay in order to let more replicas arrive. ========================================================== The delay is specified in seconds, and by default is 5 seconds. To disable ========================================================================== it entirely just set it to 0 seconds and the transfer will start ASAP. ====================================================================== repl-diskless-sync-delay 5 When diskless replication is enabled with a delay, it is possible to let ======================================================================== the replication start before the maximum delay is reached if the maximum ======================================================================== number of replicas expected have connected. Default of 0 means that the ======================================================================= maximum is not defined and Redis will wait the full delay. ========================================================== repl-diskless-sync-max-replicas 0 ----------------------------------------------------------------------------- ============================================================================= WARNING: RDB diskless load is experimental. Since in this setup the replica =========================================================================== does not immediately store an RDB on disk, it may cause data loss during ======================================================================== failovers. RDB diskless load + Redis modules not handling I/O reads may also ============================================================================ cause Redis to abort in case of I/O errors during the initial synchronization ============================================================================= stage with the master. Use only if you know what you are doing. =============================================================== ----------------------------------------------------------------------------- ============================================================================= Replica can load the RDB it reads from the replication link directly from the ============================================================================= socket, or store the RDB to a file and read that file after it was completely ============================================================================= received from the master. ========================= In many cases the disk is slower than the network, and storing and loading ========================================================================== the RDB file may increase replication time (and even increase the master's ========================================================================== Copy on Write memory and replica buffers). ========================================== However, parsing the RDB file directly from the socket may mean that we have ============================================================================ to flush the contents of the current database before the full rdb was ===================================================================== received. For this reason we have the following options: ======================================================== "disabled" - Don't use diskless load (store the rdb file to the disk first) =========================================================================== "on-empty-db" - Use diskless load only when it is completely safe. ================================================================== "swapdb" - Keep current db contents in RAM while parsing the data directly ========================================================================== from the socket. Replicas in this mode can keep serving current =============================================================== data set while replication is in progress, except for cases where ================================================================= they can't recognize master as having a data set from same ========================================================== replication history. ==================== Note that this requires sufficient memory, if you don't have it, ================================================================ you risk an OOM kill. ===================== repl-diskless-load disabled Master send PINGs to its replicas in a predefined interval. It's possible to ============================================================================ change this interval with the repl_ping_replica_period option. The default ========================================================================== value is 10 seconds. ==================== repl-ping-replica-period 10 =========================== The following option sets the replication timeout for: ====================================================== 1) Bulk transfer I/O during SYNC, from the point of view of replica. ==================================================================== 2) Master timeout from the point of view of replicas (data, pings). =================================================================== 3) Replica timeout from the point of view of masters (REPLCONF ACK pings). ========================================================================== It is important to make sure that this value is greater than the value ====================================================================== specified for repl-ping-replica-period otherwise a timeout will be detected =========================================================================== every time there is low traffic between the master and the replica. The default =============================================================================== value is 60 seconds. ==================== repl-timeout 60 =============== Disable TCP_NODELAY on the replica socket after SYNC? ===================================================== If you select "yes" Redis will use a smaller number of TCP packets and ====================================================================== less bandwidth to send data to replicas. But this can add a delay for ===================================================================== the data to appear on the replica side, up to 40 milliseconds with ================================================================== Linux kernels using a default configuration. ============================================ If you select "no" the delay for data to appear on the replica side will ======================================================================== be reduced but more bandwidth will be used for replication. =========================================================== By default we optimize for low latency, but in very high traffic conditions =========================================================================== or when the master and replicas are many hops away, turning this to "yes" may ============================================================================= be a good idea. =============== repl-disable-tcp-nodelay no Set the replication backlog size. The backlog is a buffer that accumulates ========================================================================== replica data when replicas are disconnected for some time, so that when a ========================================================================= replica wants to reconnect again, often a full resync is not needed, but a ========================================================================== partial resync is enough, just passing the portion of data the replica ====================================================================== missed while disconnected. ========================== The bigger the replication backlog, the longer the replica can endure the ========================================================================= disconnect and later be able to perform a partial resynchronization. ==================================================================== The backlog is only allocated if there is at least one replica connected. ========================================================================= repl-backlog-size 1mb ===================== After a master has no connected replicas for some time, the backlog will be =========================================================================== freed. The following option configures the amount of seconds that need to ========================================================================= elapse, starting from the time the last replica disconnected, for the backlog ============================================================================= buffer to be freed. =================== Note that replicas never free the backlog for timeout, since they may be ======================================================================== promoted to masters later, and should be able to correctly "partially ===================================================================== resynchronize" with other replicas: hence they should always accumulate backlog. ================================================================================ A value of 0 means to never release the backlog. ================================================ repl-backlog-ttl 3600 ===================== The replica priority is an integer number published by Redis in the INFO ======================================================================== output. It is used by Redis Sentinel in order to select a replica to promote ============================================================================ into a master if the master is no longer working correctly. =========================================================== A replica with a low priority number is considered better for promotion, so =========================================================================== for instance if there are three replicas with priority 10, 100, 25 Sentinel =========================================================================== will pick the one with priority 10, that is the lowest. ======================================================= However a special priority of 0 marks the replica as not able to perform the ============================================================================ role of master, so a replica with priority of 0 will never be selected by ========================================================================= Redis Sentinel for promotion. ============================= By default the priority is 100. =============================== replica-priority 100 The propagation error behavior controls how Redis will behave when it is ======================================================================== unable to handle a command being processed in the replication stream from a master ================================================================================== or processed while reading from an AOF file. Errors that occur during propagation ================================================================================= are unexpected, and can cause data inconsistency. However, there are edge cases =============================================================================== in earlier versions of Redis where it was possible for the server to replicate or persist ========================================================================================= commands that would fail on future versions. For this reason the default behavior ================================================================================= is to ignore such errors and continue processing commands. ========================================================== If an application wants to ensure there is no data divergence, this configuration ================================================================================= should be set to 'panic' instead. The value can also be set to 'panic-on-replicas' ================================================================================== to only panic when a replica encounters an error on the replication stream. One of ================================================================================== these two panic values will become the default value in the future once there are ================================================================================= sufficient safety mechanisms in place to prevent false positive crashes. ======================================================================== propagation-error-behavior ignore ================================= Replica ignore disk write errors controls the behavior of a replica when it is ============================================================================== unable to persist a write command received from its master to disk. By default, =============================================================================== this configuration is set to 'no' and will crash the replica in this condition. =============================================================================== It is not recommended to change this default, however in order to be compatible =============================================================================== with older versions of Redis this config can be toggled to 'yes' which will just ================================================================================ log a warning and execute the write command it got from the master. =================================================================== replica-ignore-disk-write-errors no =================================== ----------------------------------------------------------------------------- ============================================================================= By default, Redis Sentinel includes all replicas in its reports. A replica ========================================================================== can be excluded from Redis Sentinel's announcements. An unannounced replica =========================================================================== will be ignored by the 'sentinel replicas \<master\>' command and won't be ========================================================================== exposed to Redis Sentinel's clients. ==================================== This option does not change the behavior of replica-priority. Even with ======================================================================= replica-announced set to 'no', the replica can be promoted to master. To ======================================================================== prevent this behavior, set replica-priority to 0. ================================================= replica-announced yes ===================== It is possible for a master to stop accepting writes if there are less than =========================================================================== N replicas connected, having a lag less or equal than M seconds. ================================================================ The N replicas need to be in "online" state. ============================================ The lag in seconds, that must be \<= the specified value, is calculated from ============================================================================ the last ping received from the replica, that is usually sent every second. =========================================================================== This option does not GUARANTEE that N replicas will accept the write, but ========================================================================= will limit the window of exposure for lost writes in case not enough replicas ============================================================================= are available, to the specified number of seconds. ================================================== For example to require at least 3 replicas with a lag \<= 10 seconds use: ========================================================================= min-replicas-to-write 3 ======================= min-replicas-max-lag 10 ======================= Setting one or the other to 0 disables the feature. =================================================== By default min-replicas-to-write is set to 0 (feature disabled) and =================================================================== min-replicas-max-lag is set to 10. ================================== A Redis master is able to list the address and port of the attached =================================================================== replicas in different ways. For example the "INFO replication" section ====================================================================== offers this information, which is used, among other tools, by ============================================================= Redis Sentinel in order to discover replica instances. ====================================================== Another place where this info is available is in the output of the ================================================================== "ROLE" command of a master. =========================== The listed IP address and port normally reported by a replica is ================================================================ obtained in the following way: ============================== IP: The address is auto detected by checking the peer address ============================================================= of the socket used by the replica to connect with the master. ============================================================= Port: The port is communicated by the replica during the replication ==================================================================== handshake, and is normally the port that the replica is using to ================================================================ listen for connections. ======================= However when port forwarding or Network Address Translation (NAT) is ==================================================================== used, the replica may actually be reachable via different IP and port ===================================================================== pairs. The following two options can be used by a replica in order to ===================================================================== report to its master a specific set of IP and port, so that both INFO ===================================================================== and ROLE will report those values. ================================== There is no need to use both the options if you need to override just ===================================================================== the port or the IP address. =========================== replica-announce-ip 5.5.5.5 =========================== replica-announce-port 1234 ========================== ############################### KEYS TRACKING ################################# Redis implements server assisted support for client side caching of values. =========================================================================== This is implemented using an invalidation table that remembers, using ===================================================================== a radix key indexed by key name, what clients have which keys. In turn ====================================================================== this is used in order to send invalidation messages to clients. Please ====================================================================== check this page to understand more about the feature: ===================================================== https://redis.io/topics/client-side-caching =========================================== When tracking is enabled for a client, all the read only queries are assumed ============================================================================ to be cached: this will force Redis to store information in the invalidation ============================================================================ table. When keys are modified, such information is flushed away, and ==================================================================== invalidation messages are sent to the clients. However if the workload is ========================================================================= heavily dominated by reads, Redis could use more and more memory in order ========================================================================= to track the keys fetched by many clients. ========================================== For this reason it is possible to configure a maximum fill value for the ======================================================================== invalidation table. By default it is set to 1M of keys, and once this limit =========================================================================== is reached, Redis will start to evict keys in the invalidation table ==================================================================== even if they were not modified, just to reclaim memory: this will in turn ========================================================================= force the clients to invalidate the cached values. Basically the table ====================================================================== maximum size is a trade off between the memory you want to spend server ======================================================================= side to track information about who cached what, and the ability of clients =========================================================================== to retain cached objects in memory. =================================== If you set the value to 0, it means there are no limits, and Redis will ======================================================================= retain as many keys as needed in the invalidation table. ======================================================== In the "stats" INFO section, you can find information about the number of ========================================================================= keys in the invalidation table at every given moment. ===================================================== Note: when key tracking is used in broadcasting mode, no memory is used ======================================================================= in the server side so this setting is useless. ============================================== tracking-table-max-keys 1000000 =============================== ################################## SECURITY ################################### Warning: since Redis is pretty fast, an outside user can try up to ================================================================== 1 million passwords per second against a modern box. This means that you ======================================================================== should use very strong passwords, otherwise they will be very easy to break. ============================================================================ Note that because the password is really a shared secret between the client =========================================================================== and the server, and should not be memorized by any human, the password ====================================================================== can be easily a long string from /dev/urandom or whatever, so by using a ======================================================================== long and unguessable password no brute force attack will be possible. ===================================================================== Redis ACL users are defined in the following format: ==================================================== user \<username\> ... acl rules ... =================================== For example: ============ user worker +@list +@connection \~jobs:\* on \>ffa9203c493aa99 ============================================================== The special username "default" is used for new connections. If this user ======================================================================== has the "nopass" rule, then new connections will be immediately authenticated ============================================================================= as the "default" user without the need of any password provided via the ======================================================================= AUTH command. Otherwise if the "default" user is not flagged with "nopass" ========================================================================== the connections will start in not authenticated state, and will require ======================================================================= AUTH (or the HELLO command AUTH option) in order to be authenticated and ======================================================================== start to work. ============== The ACL rules that describe what a user can do are the following: ================================================================= on Enable the user: it is possible to authenticate as this user. ================================================================ off Disable the user: it's no longer possible to authenticate ============================================================= with this user, however the already authenticated connections ============================================================= will still work. ================ skip-sanitize-payload RESTORE dump-payload sanitization is skipped. =================================================================== sanitize-payload RESTORE dump-payload is sanitized (default). ============================================================= +\<command\> Allow the execution of that command. ================================================= May be used with `|` for allowing subcommands (e.g "+config\|get") ================================================================== -\<command\> Disallow the execution of that command. ==================================================== May be used with `|` for blocking subcommands (e.g "-config\|set") ================================================================== +@\<category\> Allow the execution of all the commands in such category ======================================================================= with valid categories are like @admin, @set, @sortedset, ... ============================================================ and so forth, see the full list in the server.c file where ========================================================== the Redis command table is described and defined. ================================================= The special category @all means all the commands, but currently =============================================================== present in the server, and that will be loaded in the future ============================================================ via modules. ============ +\<command\>\|first-arg Allow a specific first argument of an otherwise ======================================================================= disabled command. It is only supported on commands with ======================================================= no sub-commands, and is not allowed as negative form ==================================================== like -SELECT\|1, only additive starting with "+". This ====================================================== feature is deprecated and may be removed in the future. ======================================================= allcommands Alias for +@all. Note that it implies the ability to execute ======================================================================== all the future commands loaded via the modules system. ====================================================== nocommands Alias for -@all. =========================== \~\<pattern\> Add a pattern of keys that can be mentioned as part of ==================================================================== commands. For instance \~\* allows all the keys. The pattern ============================================================ is a glob-style pattern like the one of KEYS. ============================================= It is possible to specify multiple patterns. ============================================ %R\~\<pattern\> Add key read pattern that specifies which keys can be read ========================================================================== from. ===== %W\~\<pattern\> Add key write pattern that specifies which keys can be ====================================================================== written to. =========== allkeys Alias for \~\* ====================== resetkeys Flush the list of allowed keys patterns. ================================================== \&\<pattern\> Add a glob-style pattern of Pub/Sub channels that can be ====================================================================== accessed by the user. It is possible to specify multiple channel ================================================================ patterns. ========= allchannels Alias for \&\* ========================== resetchannels Flush the list of allowed channel patterns. ========================================================= \>\<password\> Add this password to the list of valid password for the user. ============================================================================ For example \>mypass will add "mypass" to the list. =================================================== This directive clears the "nopass" flag (see later). ==================================================== \<\<password\> Remove this password from the list of valid passwords. ===================================================================== nopass All the set passwords of the user are removed, and the user ================================================================== is flagged as requiring no password: it means that every ======================================================== password will work against this user. If this directive is ========================================================== used for the default user, every new connection will be ======================================================= immediately authenticated with the default user without ======================================================= any explicit AUTH command required. Note that the "resetpass" ============================================================= directive will clear this condition. ==================================== resetpass Flush the list of allowed passwords. Moreover removes the =================================================================== "nopass" status. After "resetpass" the user has no associated ============================================================= passwords and there is no way to authenticate without adding ============================================================ some password (or setting it as "nopass" later). ================================================ reset Performs the following actions: resetpass, resetkeys, off, ================================================================ -@all. The user returns to the same state it has immediately ============================================================ after its creation. =================== (\<options\>) Create a new selector with the options specified within the ========================================================================= parentheses and attach it to the user. Each option should be ============================================================ space separated. The first character must be ( and the last =========================================================== character must be ). ==================== clearselectors Remove all of the currently attached selectors. ============================================================== Note this does not change the "root" user permissions, ====================================================== which are the permissions directly applied onto the =================================================== user (outside the parentheses). =============================== ACL rules can be specified in any order: for instance you can start with ======================================================================== passwords, then flags, or key patterns. However note that the additive ====================================================================== and subtractive rules will CHANGE MEANING depending on the ordering. ==================================================================== For instance see the following example: ======================================= user alice on +@all -DEBUG \~\* \>somepassword ============================================== This will allow "alice" to use all the commands with the exception of the ========================================================================= DEBUG command, since +@all added all the commands to the set of the commands ============================================================================ alice can use, and later DEBUG was removed. However if we invert the order ========================================================================== of two ACL rules the result will be different: ============================================== user alice on -DEBUG +@all \~\* \>somepassword ============================================== Now DEBUG was removed when alice had yet no commands in the set of allowed ========================================================================== commands, later all the commands are added, so the user will be able to ======================================================================= execute everything. =================== Basically ACL rules are processed left-to-right. ================================================ The following is a list of command categories and their meanings: ================================================================= \* keyspace - Writing or reading from keys, databases, or their metadata ======================================================================== in a type agnostic way. Includes DEL, RESTORE, DUMP, RENAME, EXISTS, DBSIZE, ============================================================================ KEYS, EXPIRE, TTL, FLUSHALL, etc. Commands that may modify the keyspace, ======================================================================== key or metadata will also have `write` category. Commands that only read ======================================================================== the keyspace, key or metadata will have the `read` category. ============================================================ \* read - Reading from keys (values or metadata). Note that commands that don't =============================================================================== interact with keys, will not have either `read` or `write`. =========================================================== \* write - Writing to keys (values or metadata) =============================================== \* admin - Administrative commands. Normal applications will never need to use ============================================================================== these. Includes REPLICAOF, CONFIG, DEBUG, SAVE, MONITOR, ACL, SHUTDOWN, etc. ============================================================================ \* dangerous - Potentially dangerous (each should be considered with care for ============================================================================= various reasons). This includes FLUSHALL, MIGRATE, RESTORE, SORT, KEYS, ======================================================================= CLIENT, DEBUG, INFO, CONFIG, SAVE, REPLICAOF, etc. ================================================== \* connection - Commands affecting the connection or other connections. ======================================================================= This includes AUTH, SELECT, COMMAND, CLIENT, ECHO, PING, etc. ============================================================= \* blocking - Potentially blocking the connection until released by another =========================================================================== command. ======== \* fast - Fast O(1) commands. May loop on the number of arguments, but not the ============================================================================== number of elements in the key. ============================== \* slow - All commands that are not Fast. ========================================= \* pubsub - PUBLISH / SUBSCRIBE related ======================================= \* transaction - WATCH / MULTI / EXEC related commands. ======================================================= \* scripting - Scripting related. ================================= \* set - Data type: sets related. ================================= \* sortedset - Data type: zsets related. ======================================== \* list - Data type: lists related. =================================== \* hash - Data type: hashes related. ==================================== \* string - Data type: strings related. ======================================= \* bitmap - Data type: bitmaps related. ======================================= \* hyperloglog - Data type: hyperloglog related. ================================================ \* geo - Data type: geo related. ================================ \* stream - Data type: streams related. ======================================= For more information about ACL configuration please refer to ============================================================ the Redis web site at https://redis.io/topics/acl ================================================= ACL LOG ======= The ACL Log tracks failed commands and authentication events associated ======================================================================= with ACLs. The ACL Log is useful to troubleshoot failed commands blocked ======================================================================== by ACLs. The ACL Log is stored in memory. You can reclaim memory with ===================================================================== ACL LOG RESET. Define the maximum entry length of the ACL Log below. ==================================================================== acllog-max-len 128 Using an external ACL file ========================== Instead of configuring users here in this file, it is possible to use ===================================================================== a stand-alone file just listing users. The two methods cannot be mixed: ======================================================================= if you configure users here and at the same time you activate the external ========================================================================== ACL file, the server will refuse to start. ========================================== The format of the external ACL user file is exactly the same as the =================================================================== format that is used inside redis.conf to describe users. ======================================================== aclfile /etc/redis/users.acl ============================ IMPORTANT NOTE: starting with Redis 6 "requirepass" is just a compatibility =========================================================================== layer on top of the new ACL system. The option effect will be just setting ========================================================================== the password for the default user. Clients will still authenticate using ======================================================================== AUTH \<password\> as usually, or more explicitly with AUTH default \<password\> =============================================================================== if they follow the new protocol: both will work. ================================================ The requirepass is not compatible with aclfile option and the ACL LOAD ====================================================================== command, these will cause requirepass to be ignored. ==================================================== requirepass 12345678 ==================== New users are initialized with restrictive permissions by default, via the ========================================================================== equivalent of this ACL rule 'off resetkeys -@all'. Starting with Redis 6.2, it ============================================================================== is possible to manage access to Pub/Sub channels with ACL rules as well. The ============================================================================ default Pub/Sub channels permission if new users is controlled by the ===================================================================== acl-pubsub-default configuration directive, which accepts one of these values: ============================================================================== allchannels: grants access to all Pub/Sub channels ================================================== resetchannels: revokes access to all Pub/Sub channels ===================================================== From Redis 7.0, acl-pubsub-default defaults to 'resetchannels' permission. ========================================================================== acl-pubsub-default resetchannels ================================ Command renaming (DEPRECATED). ============================== ------------------------------------------------------------------------ ======================================================================== WARNING: avoid using this option if possible. Instead use ACLs to remove ======================================================================== commands from the default user, and put them only in some admin user you ======================================================================== create for administrative purposes. =================================== ------------------------------------------------------------------------ ======================================================================== It is possible to change the name of dangerous commands in a shared =================================================================== environment. For instance the CONFIG command may be renamed into something ========================================================================== hard to guess so that it will still be available for internal-use tools ======================================================================= but not available for general clients. ====================================== Example: ======== rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52 ============================================================== It is also possible to completely kill a command by renaming it into ==================================================================== an empty string: ================ rename-command CONFIG "" ======================== Please note that changing the name of commands that are logged into the ======================================================================= AOF file or transmitted to replicas may cause problems. ======================================================= ################################### CLIENTS #################################### Set the max number of connected clients at the same time. By default ==================================================================== this limit is set to 10000 clients, however if the Redis server is not ====================================================================== able to configure the process file limit to allow for the specified limit ========================================================================= the max number of allowed clients is set to the current file limit ================================================================== minus 32 (as Redis reserves a few file descriptors for internal uses). ====================================================================== Once the limit is reached Redis will close all the new connections sending ========================================================================== an error 'max number of clients reached'. ========================================= IMPORTANT: When Redis Cluster is used, the max number of connections is also ============================================================================ shared with the cluster bus: every node in the cluster will use two =================================================================== connections, one incoming and another outgoing. It is important to size the =========================================================================== limit accordingly in case of very large clusters. ================================================= maxclients 10000 ================ ############################## MEMORY MANAGEMENT ################################ Set a memory usage limit to the specified amount of bytes. ========================================================== When the memory limit is reached Redis will try to remove keys ============================================================== according to the eviction policy selected (see maxmemory-policy). ================================================================= If Redis can't remove keys according to the policy, or if the policy is ======================================================================= set to 'noeviction', Redis will start to reply with errors to commands ====================================================================== that would use more memory, like SET, LPUSH, and so on, and will continue ========================================================================= to reply to read-only commands like GET. ======================================== This option is usually useful when using Redis as an LRU or LFU cache, or to ============================================================================ set a hard memory limit for an instance (using the 'noeviction' policy). ======================================================================== WARNING: If you have replicas attached to an instance with maxmemory on, ======================================================================== the size of the output buffers needed to feed the replicas are subtracted ========================================================================= from the used memory count, so that network problems / resyncs will =================================================================== not trigger a loop where keys are evicted, and in turn the output ================================================================= buffer of replicas is full with DELs of keys evicted triggering the deletion ============================================================================ of more keys, and so forth until the database is completely emptied. ==================================================================== In short... if you have replicas attached it is suggested that you set a lower ============================================================================== limit for maxmemory so that there is some free RAM on the system for replica ============================================================================ output buffers (but this is not needed if the policy is 'noeviction'). ====================================================================== maxmemory \<bytes\> =================== MAXMEMORY POLICY: how Redis will select what to remove when maxmemory ===================================================================== is reached. You can select one from the following behaviors: ============================================================ volatile-lru -\> Evict using approximated LRU, only keys with an expire set. ============================================================================ allkeys-lru -\> Evict any key using approximated LRU. ===================================================== volatile-lfu -\> Evict using approximated LFU, only keys with an expire set. ============================================================================ allkeys-lfu -\> Evict any key using approximated LFU. ===================================================== volatile-random -\> Remove a random key having an expire set. ============================================================= allkeys-random -\> Remove a random key, any key. ================================================ volatile-ttl -\> Remove the key with the nearest expire time (minor TTL) ======================================================================== noeviction -\> Don't evict anything, just return an error on write operations. ============================================================================== LRU means Least Recently Used ============================= LFU means Least Frequently Used =============================== Both LRU, LFU and volatile-ttl are implemented using approximated ================================================================= randomized algorithms. ====================== Note: with any of the above policies, when there are no suitable keys for ========================================================================= eviction, Redis will return an error on write operations that require ===================================================================== more memory. These are usually commands that create new keys, add data or ========================================================================= modify existing keys. A few examples are: SET, INCR, HSET, LPUSH, SUNIONSTORE, ============================================================================== SORT (due to the STORE argument), and EXEC (if the transaction includes any =========================================================================== command that requires memory). ============================== The default is: =============== maxmemory-policy noeviction =========================== LRU, LFU and minimal TTL algorithms are not precise algorithms but approximated =============================================================================== algorithms (in order to save memory), so you can tune it for speed or ===================================================================== accuracy. By default Redis will check five keys and pick the one that was ========================================================================= used least recently, you can change the sample size using the following ======================================================================= configuration directive. ======================== The default of 5 produces good enough results. 10 Approximates very closely =========================================================================== true LRU but costs more CPU. 3 is faster but not very accurate. =============================================================== maxmemory-samples 5 =================== Eviction processing is designed to function well with the default setting. ========================================================================== If there is an unusually large amount of write traffic, this value may need to ============================================================================== be increased. Decreasing this value may reduce latency at the risk of ===================================================================== eviction processing effectiveness ================================= 0 = minimum latency, 10 = default, 100 = process without regard to latency ========================================================================== maxmemory-eviction-tenacity 10 ============================== Starting from Redis 5, by default a replica will ignore its maxmemory setting ============================================================================= (unless it is promoted to master after a failover or manually). It means ======================================================================== that the eviction of keys will be just handled by the master, sending the ========================================================================= DEL commands to the replica as keys evict in the master side. ============================================================= This behavior ensures that masters and replicas stay consistent, and is usually =============================================================================== what you want, however if your replica is writable, or you want the replica =========================================================================== to have a different memory setting, and you are sure all the writes performed ============================================================================= to the replica are idempotent, then you may change this default (but be sure ============================================================================ to understand what you are doing). ================================== Note that since the replica by default does not evict, it may end using more ============================================================================ memory than the one set via maxmemory (there are certain buffers that may ========================================================================= be larger on the replica, or data structures may sometimes take more memory =========================================================================== and so forth). So make sure you monitor your replicas and make sure they ======================================================================== have enough memory to never hit a real out-of-memory condition before the ========================================================================= master hits the configured maxmemory setting. ============================================= replica-ignore-maxmemory yes ============================ Redis reclaims expired keys in two ways: upon access when those keys are ======================================================================== found to be expired, and also in background, in what is called the ================================================================== "active expire key". The key space is slowly and interactively scanned ====================================================================== looking for expired keys to reclaim, so that it is possible to free memory ========================================================================== of keys that are expired and will never be accessed again in a short time. ========================================================================== The default effort of the expire cycle will try to avoid having more than ========================================================================= ten percent of expired keys still in memory, and will try to avoid consuming ============================================================================ more than 25% of total memory and to add latency to the system. However ======================================================================= it is possible to increase the expire "effort" that is normally set to ====================================================================== "1", to a greater value, up to the value "10". At its maximum value the ======================================================================= system will use more CPU, longer cycles (and technically may introduce ====================================================================== more latency), and will tolerate less already expired keys still present ======================================================================== in the system. It's a tradeoff between memory, CPU and latency. =============================================================== active-expire-effort 1 ====================== ############################# LAZY FREEING #################################### Redis has two primitives to delete keys. One is called DEL and is a blocking ============================================================================ deletion of the object. It means that the server stops processing new commands ============================================================================== in order to reclaim all the memory associated with an object in a synchronous ============================================================================= way. If the key deleted is associated with a small object, the time needed ========================================================================== in order to execute the DEL command is very small and comparable to most other ============================================================================== O(1) or O(log_N) commands in Redis. However if the key is associated with an ============================================================================ aggregated value containing millions of elements, the server can block for ========================================================================== a long time (even seconds) in order to complete the operation. ============================================================== For the above reasons Redis also offers non blocking deletion primitives ======================================================================== such as UNLINK (non blocking DEL) and the ASYNC option of FLUSHALL and ====================================================================== FLUSHDB commands, in order to reclaim memory in background. Those commands ========================================================================== are executed in constant time. Another thread will incrementally free the ========================================================================= object in the background as fast as possible. ============================================= DEL, UNLINK and ASYNC option of FLUSHALL and FLUSHDB are user-controlled. ========================================================================= It's up to the design of the application to understand when it is a good ======================================================================== idea to use one or the other. However the Redis server sometimes has to ======================================================================= delete keys or flush the whole database as a side effect of other operations. ============================================================================= Specifically Redis deletes objects independently of a user call in the ====================================================================== following scenarios: ==================== 1) On eviction, because of the maxmemory and maxmemory policy configurations, ============================================================================= in order to make room for new data, without going over the specified ==================================================================== memory limit. ============= 2) Because of expire: when a key with an associated time to live (see the ========================================================================= EXPIRE command) must be deleted from memory. ============================================ 3) Because of a side effect of a command that stores data on a key that may =========================================================================== already exist. For example the RENAME command may delete the old key ==================================================================== content when it is replaced with another one. Similarly SUNIONSTORE =================================================================== or SORT with STORE option may delete existing keys. The SET command =================================================================== itself removes any old content of the specified key in order to replace ======================================================================= it with the specified string. ============================= 4) During replication, when a replica performs a full resynchronization with ============================================================================ its master, the content of the whole database is removed in order to ==================================================================== load the RDB file just transferred. =================================== In all the above cases the default is to delete objects in a blocking way, ========================================================================== like if DEL was called. However you can configure each case specifically ======================================================================== in order to instead release memory in a non-blocking way like if UNLINK ======================================================================= was called, using the following configuration directives. ========================================================= lazyfree-lazy-eviction no lazyfree-lazy-expire no lazyfree-lazy-server-del no replica-lazy-flush no It is also possible, for the case when to replace the user code DEL calls ========================================================================= with UNLINK calls is not easy, to modify the default behavior of the DEL ======================================================================== command to act exactly like UNLINK, using the following configuration ===================================================================== directive: ========== lazyfree-lazy-user-del no FLUSHDB, FLUSHALL, SCRIPT FLUSH and FUNCTION FLUSH support both asynchronous and synchronous ============================================================================================ deletion, which can be controlled by passing the \[SYNC\|ASYNC\] flags into the =============================================================================== commands. When neither flag is passed, this directive will be used to determine =============================================================================== if the data should be deleted asynchronously. ============================================= lazyfree-lazy-user-flush no ################################ THREADED I/O ################################# Redis is mostly single threaded, however there are certain threaded =================================================================== operations such as UNLINK, slow I/O accesses and other things that are ====================================================================== performed on side threads. ========================== Now it is also possible to handle Redis clients socket reads and writes ======================================================================= in different I/O threads. Since especially writing is so slow, normally ======================================================================= Redis users use pipelining in order to speed up the Redis performances per ========================================================================== core, and spawn multiple instances in order to scale more. Using I/O ==================================================================== threads it is possible to easily speedup two times Redis without resorting ========================================================================== to pipelining nor sharding of the instance. =========================================== By default threading is disabled, we suggest enabling it only in machines ========================================================================= that have at least 4 or more cores, leaving at least one spare core. ==================================================================== Using more than 8 threads is unlikely to help much. We also recommend using =========================================================================== threaded I/O only if you actually have performance problems, with Redis ======================================================================= instances being able to use a quite big percentage of CPU time, otherwise ========================================================================= there is no point in using this feature. ======================================== So for instance if you have a four cores boxes, try to use 2 or 3 I/O ===================================================================== threads, if you have a 8 cores, try to use 6 threads. In order to ================================================================= enable I/O threads use the following configuration directive: ============================================================= io-threads 4 ============ Setting io-threads to 1 will just use the main thread as usual. =============================================================== When I/O threads are enabled, we only use threads for writes, that is ===================================================================== to thread the write(2) syscall and transfer the client buffers to the ===================================================================== socket. However it is also possible to enable threading of reads and ==================================================================== protocol parsing using the following configuration directive, by setting ======================================================================== it to yes: ========== io-threads-do-reads no ====================== Usually threading reads doesn't help much. ========================================== NOTE 1: This configuration directive cannot be changed at runtime via ===================================================================== CONFIG SET. Also, this feature currently does not work when SSL is ================================================================== enabled. ======== NOTE 2: If you want to test the Redis speedup using redis-benchmark, make ========================================================================= sure you also run the benchmark itself in threaded mode, using the ================================================================== --threads option to match the number of Redis threads, otherwise you'll not =========================================================================== be able to notice the improvements. =================================== ############################ KERNEL OOM CONTROL ############################## On Linux, it is possible to hint the kernel OOM killer on what processes ======================================================================== should be killed first when out of memory. ========================================== Enabling this feature makes Redis actively control the oom_score_adj value ========================================================================== for all its processes, depending on their role. The default scores will ======================================================================= attempt to have background child processes killed before all others, and ======================================================================== replicas killed before masters. =============================== Redis supports these options: ============================= no: Don't make changes to oom-score-adj (default). ================================================== yes: Alias to "relative" see below. =================================== absolute: Values in oom-score-adj-values are written as is to the kernel. ========================================================================= relative: Values are used relative to the initial value of oom_score_adj when ============================================================================= the server starts and are then clamped to a range of -1000 to 1000. =================================================================== Because typically the initial value is 0, they will often match the =================================================================== absolute values. ================ oom-score-adj no When oom-score-adj is used, this directive controls the specific values used ============================================================================ for master, replica and background child processes. Values range -2000 to ========================================================================= 2000 (higher means more likely to be killed). ============================================= Unprivileged processes (not root, and without CAP_SYS_RESOURCE capabilities) ============================================================================ can freely increase their value, but not decrease it below its initial ====================================================================== settings. This means that setting oom-score-adj to "relative" and setting the ============================================================================= oom-score-adj-values to positive values will always succeed. ============================================================ oom-score-adj-values 0 200 800 #################### KERNEL transparent hugepage CONTROL ###################### Usually the kernel Transparent Huge Pages control is set to "madvise" or ======================================================================== or "never" by default (/sys/kernel/mm/transparent_hugepage/enabled), in which ============================================================================= case this config has no effect. On systems in which it is set to "always", ========================================================================== redis will attempt to disable it specifically for the redis process in order ============================================================================ to avoid latency problems specifically with fork(2) and CoW. ============================================================ If for some reason you prefer to keep it enabled, you can set this config to ============================================================================ "no" and the kernel global to "always". ======================================= disable-thp yes ############################## APPEND ONLY MODE ############################### By default Redis asynchronously dumps the dataset on disk. This mode is ======================================================================= good enough in many applications, but an issue with the Redis process or ======================================================================== a power outage may result into a few minutes of writes lost (depending on ========================================================================= the configured save points). ============================ The Append Only File is an alternative persistence mode that provides ===================================================================== much better durability. For instance using the default data fsync policy ======================================================================== (see later in the config file) Redis can lose just one second of writes in a ============================================================================ dramatic event like a server power outage, or a single write if something ========================================================================= wrong with the Redis process itself happens, but the operating system is ======================================================================== still running correctly. ======================== AOF and RDB persistence can be enabled at the same time without problems. ========================================================================= If the AOF is enabled on startup Redis will load the AOF, that is the file ========================================================================== with the better durability guarantees. ====================================== Please check https://redis.io/topics/persistence for more information. ====================================================================== appendonly no The base name of the append only file. ====================================== Redis 7 and newer use a set of append-only files to persist the dataset ======================================================================= and changes applied to it. There are two basic types of files in use: ===================================================================== - Base files, which are a snapshot representing the complete state of the ========================================================================= dataset at the time the file was created. Base files can be either in ===================================================================== the form of RDB (binary serialized) or AOF (textual commands). ============================================================== - Incremental files, which contain additional commands that were applied ======================================================================== to the dataset following the previous file. =========================================== In addition, manifest files are used to track the files and the order in ======================================================================== which they were created and should be applied. ============================================== Append-only file names are created by Redis following a specific pattern. ========================================================================= The file name's prefix is based on the 'appendfilename' configuration ===================================================================== parameter, followed by additional information about the sequence and type. ========================================================================== For example, if appendfilename is set to appendonly.aof, the following file =========================================================================== names could be derived: ======================= - appendonly.aof.1.base.rdb as a base file. =========================================== - appendonly.aof.1.incr.aof, appendonly.aof.2.incr.aof as incremental files. ============================================================================ - appendonly.aof.manifest as a manifest file. ============================================= appendfilename "appendonly.aof" For convenience, Redis stores all persistent append-only files in a dedicated ============================================================================= directory. The name of the directory is determined by the appenddirname ======================================================================= configuration parameter. ======================== appenddirname "appendonlydir" The fsync() call tells the Operating System to actually write data on disk ========================================================================== instead of waiting for more data in the output buffer. Some OS will really flush ================================================================================ data on disk, some other OS will just try to do it ASAP. ======================================================== Redis supports three different modes: ===================================== no: don't fsync, just let the OS flush the data when it wants. Faster. ====================================================================== always: fsync after every write to the append only log. Slow, Safest. ===================================================================== everysec: fsync only one time every second. Compromise. ======================================================= The default is "everysec", as that's usually the right compromise between ========================================================================= speed and data safety. It's up to you to understand if you can relax this to ============================================================================ "no" that will let the operating system flush the output buffer when ==================================================================== it wants, for better performances (but if you can live with the idea of ======================================================================= some data loss consider the default persistence mode that's snapshotting), ========================================================================== or on the contrary, use "always" that's very slow but a bit safer than ====================================================================== everysec. ========= More details please check the following article: ================================================ http://antirez.com/post/redis-persistence-demystified.html ========================================================== If unsure, use "everysec". ========================== appendfsync always ================== appendfsync everysec appendfsync no ============== When the AOF fsync policy is set to always or everysec, and a background ======================================================================== saving process (a background save or AOF log background rewriting) is ===================================================================== performing a lot of I/O against the disk, in some Linux configurations ====================================================================== Redis may block too long on the fsync() call. Note that there is no fix for =========================================================================== this currently, as even performing fsync in a different thread will block ========================================================================= our synchronous write(2) call. ============================== In order to mitigate this problem it's possible to use the following option =========================================================================== that will prevent fsync() from being called in the main process while a ======================================================================= BGSAVE or BGREWRITEAOF is in progress. ====================================== This means that while another child is saving, the durability of Redis is ========================================================================= the same as "appendfsync no". In practical terms, this means that it is ======================================================================= possible to lose up to 30 seconds of log in the worst scenario (with the ======================================================================== default Linux settings). ======================== If you have latency problems turn this to "yes". Otherwise leave it as ====================================================================== "no" that is the safest pick from the point of view of durability. ================================================================== no-appendfsync-on-rewrite no Automatic rewrite of the append only file. ========================================== Redis is able to automatically rewrite the log file implicitly calling ====================================================================== BGREWRITEAOF when the AOF log size grows by the specified percentage. ===================================================================== This is how it works: Redis remembers the size of the AOF file after the ======================================================================== latest rewrite (if no rewrite has happened since the restart, the size of ========================================================================= the AOF at startup is used). ============================ This base size is compared to the current size. If the current size is ====================================================================== bigger than the specified percentage, the rewrite is triggered. Also ==================================================================== you need to specify a minimal size for the AOF file to be rewritten, this ========================================================================= is useful to avoid rewriting the AOF file even if the percentage increase ========================================================================= is reached but it is still pretty small. ======================================== Specify a percentage of zero in order to disable the automatic AOF ================================================================== rewrite feature. ================ auto-aof-rewrite-percentage 100 auto-aof-rewrite-min-size 64mb An AOF file may be found to be truncated at the end during the Redis ==================================================================== startup process, when the AOF data gets loaded back into memory. ================================================================ This may happen when the system where Redis is running ====================================================== crashes, especially when an ext4 filesystem is mounted without the ================================================================== data=ordered option (however this can't happen when Redis itself ================================================================ crashes or aborts but the operating system still works correctly). ================================================================== Redis can either exit with an error when this happens, or load as much ====================================================================== data as possible (the default now) and start if the AOF file is found ===================================================================== to be truncated at the end. The following option controls this behavior. ======================================================================== If aof-load-truncated is set to yes, a truncated AOF file is loaded and ======================================================================= the Redis server starts emitting a log to inform the user of the event. ======================================================================= Otherwise if the option is set to no, the server aborts with an error ===================================================================== and refuses to start. When the option is set to no, the user requires ===================================================================== to fix the AOF file using the "redis-check-aof" utility before to restart ========================================================================= the server. =========== Note that if the AOF file will be found to be corrupted in the middle ===================================================================== the server will still exit with an error. This option only applies when ======================================================================= Redis will try to read more data from the AOF file but not enough bytes ======================================================================= will be found. ============== aof-load-truncated yes Redis can create append-only base files in either RDB or AOF formats. Using =========================================================================== the RDB format is always faster and more efficient, and disabling it is only ============================================================================ supported for backward compatibility purposes. ============================================== aof-use-rdb-preamble yes Redis supports recording timestamp annotations in the AOF to support restoring ============================================================================== the data from a specific point-in-time. However, using this capability changes ============================================================================== the AOF format in a way that may not be compatible with existing AOF parsers. ============================================================================= aof-timestamp-enabled no ################################ SHUTDOWN ##################################### Maximum time to wait for replicas when shutting down, in seconds. ================================================================= During shut down, a grace period allows any lagging replicas to catch up with ============================================================================= the latest replication offset before the master exists. This period can ======================================================================= prevent data loss, especially for deployments without configured disk backups. ============================================================================== The 'shutdown-timeout' value is the grace period's duration in seconds. It is ============================================================================= only applicable when the instance has replicas. To disable the feature, set =========================================================================== the value to 0. =============== shutdown-timeout 10 =================== When Redis receives a SIGINT or SIGTERM, shutdown is initiated and by default ============================================================================= an RDB snapshot is written to disk in a blocking operation if save points are configured. ========================================================================================= The options used on signaled shutdown can include the following values: ======================================================================= default: Saves RDB snapshot only if save points are configured. =============================================================== Waits for lagging replicas to catch up. ======================================= save: Forces a DB saving operation even if no save points are configured. ========================================================================= nosave: Prevents DB saving operation even if one or more save points are configured. ==================================================================================== now: Skips waiting for lagging replicas. ======================================== force: Ignores any errors that would normally prevent the server from exiting. ============================================================================== Any combination of values is allowed as long as "save" and "nosave" are not set simultaneously. =============================================================================================== Example: "nosave force now" =========================== shutdown-on-sigint default ========================== shutdown-on-sigterm default =========================== ################ NON-DETERMINISTIC LONG BLOCKING COMMANDS ##################### Maximum time in milliseconds for EVAL scripts, functions and in some cases ========================================================================== modules' commands before Redis can start processing or rejecting other clients. =============================================================================== If the maximum execution time is reached Redis will start to reply to most ========================================================================== commands with a BUSY error. =========================== In this state Redis will only allow a handful of commands to be executed. ========================================================================= For instance, SCRIPT KILL, FUNCTION KILL, SHUTDOWN NOSAVE and possibly some =========================================================================== module specific 'allow-busy' commands. ====================================== SCRIPT KILL and FUNCTION KILL will only be able to stop a script that did not ============================================================================= yet call any write commands, so SHUTDOWN NOSAVE may be the only way to stop =========================================================================== the server in the case a write command was already issued by the script when ============================================================================ the user doesn't want to wait for the natural termination of the script. ======================================================================== The default is 5 seconds. It is possible to set it to 0 or a negative value =========================================================================== to disable this mechanism (uninterrupted execution). Note that in the past ========================================================================== this config had a different name, which is now an alias, so both of these do ============================================================================ the same: ========= lua-time-limit 5000 =================== busy-reply-threshold 5000 ========================= ################################ REDIS CLUSTER ############################### Normal Redis instances can't be part of a Redis Cluster; only nodes that are ============================================================================ started as cluster nodes can. In order to start a Redis instance as a ===================================================================== cluster node enable the cluster support uncommenting the following: =================================================================== cluster-enabled yes =================== Every cluster node has a cluster configuration file. This file is not ===================================================================== intended to be edited by hand. It is created and updated by Redis nodes. ======================================================================== Every Redis Cluster node requires a different cluster configuration file. ========================================================================= Make sure that instances running in the same system do not have =============================================================== overlapping cluster configuration file names. ============================================= cluster-config-file nodes-6379.conf =================================== Cluster node timeout is the amount of milliseconds a node must be unreachable ============================================================================= for it to be considered in failure state. ========================================= Most other internal time limits are a multiple of the node timeout. =================================================================== cluster-node-timeout 15000 ========================== The cluster port is the port that the cluster bus will listen for inbound connections on. When set ================================================================================================== to the default value, 0, it will be bound to the command port + 10000. Setting this value requires ================================================================================================== you to specify the cluster bus port when executing cluster meet. ================================================================ cluster-port 0 ============== A replica of a failing master will avoid to start a failover if its data ======================================================================== looks too old. ============== There is no simple way for a replica to actually have an exact measure of ========================================================================= its "data age", so the following two checks are performed: ========================================================== 1) If there are multiple replicas able to failover, they exchange messages ========================================================================== in order to try to give an advantage to the replica with the best ================================================================= replication offset (more data from the master processed). ========================================================= Replicas will try to get their rank by offset, and apply to the start ===================================================================== of the failover a delay proportional to their rank. =================================================== 2) Every single replica computes the time of the last interaction with ====================================================================== its master. This can be the last ping or command received (if the master ======================================================================== is still in the "connected" state), or the time that elapsed since the ====================================================================== disconnection with the master (if the replication link is currently down). ========================================================================== If the last interaction is too old, the replica will not try to failover ======================================================================== at all. ======= The point "2" can be tuned by user. Specifically a replica will not perform =========================================================================== the failover if, since the last interaction with the master, the time ===================================================================== elapsed is greater than: ======================== (node-timeout \* cluster-replica-validity-factor) + repl-ping-replica-period ============================================================================ So for example if node-timeout is 30 seconds, and the cluster-replica-validity-factor ===================================================================================== is 10, and assuming a default repl-ping-replica-period of 10 seconds, the ========================================================================= replica will not try to failover if it was not able to talk with the master =========================================================================== for longer than 310 seconds. ============================ A large cluster-replica-validity-factor may allow replicas with too old data to failover ======================================================================================== a master, while a too small value may prevent the cluster from being able to ============================================================================ elect a replica at all. ======================= For maximum availability, it is possible to set the cluster-replica-validity-factor =================================================================================== to a value of 0, which means, that replicas will always try to failover the =========================================================================== master regardless of the last time they interacted with the master. =================================================================== (However they'll always try to apply a delay proportional to their ================================================================== offset rank). ============= Zero is the only value able to guarantee that when all the partitions heal ========================================================================== the cluster will always be able to continue. ============================================ cluster-replica-validity-factor 10 ================================== Cluster replicas are able to migrate to orphaned masters, that are masters ========================================================================== that are left without working replicas. This improves the cluster ability ========================================================================= to resist to failures as otherwise an orphaned master can't be failed over ========================================================================== in case of failure if it has no working replicas. ================================================= Replicas migrate to orphaned masters only if there are still at least a ======================================================================= given number of other working replicas for their old master. This number ======================================================================== is the "migration barrier". A migration barrier of 1 means that a replica ========================================================================= will migrate only if there is at least 1 other working replica for its master ============================================================================= and so forth. It usually reflects the number of replicas you want for every =========================================================================== master in your cluster. ======================= Default is 1 (replicas migrate only if their masters remain with at least ========================================================================= one replica). To disable migration just set it to a very large value or ======================================================================= set cluster-allow-replica-migration to 'no'. ============================================ A value of 0 can be set but is useful only for debugging and dangerous ====================================================================== in production. ============== cluster-migration-barrier 1 =========================== Turning off this option allows to use less automatic cluster configuration. =========================================================================== It both disables migration to orphaned masters and migration from masters ========================================================================= that became empty. ================== Default is 'yes' (allow automatic migrations). ============================================== cluster-allow-replica-migration yes =================================== By default Redis Cluster nodes stop accepting queries if they detect there ========================================================================== is at least a hash slot uncovered (no available node is serving it). ==================================================================== This way if the cluster is partially down (for example a range of hash slots ============================================================================ are no longer covered) all the cluster becomes, eventually, unavailable. ======================================================================== It automatically returns available as soon as all the slots are covered again. ============================================================================== However sometimes you want the subset of the cluster which is working, ====================================================================== to continue to accept queries for the part of the key space that is still ========================================================================= covered. In order to do so, just set the cluster-require-full-coverage ====================================================================== option to no. ============= cluster-require-full-coverage yes ================================= This option, when set to yes, prevents replicas from trying to failover its =========================================================================== master during master failures. However the replica can still perform a ====================================================================== manual failover, if forced to do so. ==================================== This is useful in different scenarios, especially in the case of multiple ========================================================================= data center operations, where we want one side to never be promoted if not ========================================================================== in the case of a total DC failure. ================================== cluster-replica-no-failover no ============================== This option, when set to yes, allows nodes to serve read traffic while the ========================================================================== cluster is in a down state, as long as it believes it owns the slots. ===================================================================== This is useful for two cases. The first case is for when an application ======================================================================= doesn't require consistency of data during node failures or network partitions. =============================================================================== One example of this is a cache, where as long as the node has the data it ========================================================================= should be able to serve it. =========================== The second use case is for configurations that don't meet the recommended ========================================================================= three shards but want to enable cluster mode and scale later. A =============================================================== master outage in a 1 or 2 shard configuration causes a read/write outage to the =============================================================================== entire cluster without this option set, with it set there is only a write outage. ================================================================================= Without a quorum of masters, slot ownership will not change automatically. ========================================================================== cluster-allow-reads-when-down no ================================ This option, when set to yes, allows nodes to serve pubsub shard traffic while ============================================================================== the cluster is in a down state, as long as it believes it owns the slots. ========================================================================= This is useful if the application would like to use the pubsub feature even when ================================================================================ the cluster global stable state is not OK. If the application wants to make sure only ===================================================================================== one shard is serving a given channel, this feature should be kept as yes. ========================================================================= cluster-allow-pubsubshard-when-down yes ======================================= Cluster link send buffer limit is the limit on the memory usage of an individual ================================================================================ cluster bus link's send buffer in bytes. Cluster links would be freed if they exceed ==================================================================================== this limit. This is to primarily prevent send buffers from growing unbounded on links ===================================================================================== toward slow peers (E.g. PubSub messages being piled up). ======================================================== This limit is disabled by default. Enable this limit when 'mem_cluster_links' INFO field ======================================================================================== and/or 'send-buffer-allocated' entries in the 'CLUSTER LINKS\` command output continuously increase. ==================================================================================================== Minimum limit of 1gb is recommended so that cluster link buffer can fit in at least a single ============================================================================================ PubSub message by default. (client-query-buffer-limit default value is 1gb) =========================================================================== cluster-link-sendbuf-limit 0 ============================ Clusters can configure their announced hostname using this config. This is a common use case for ================================================================================================ applications that need to use TLS Server Name Indication (SNI) or dealing with DNS based ======================================================================================== routing. By default this value is only shown as additional metadata in the CLUSTER SLOTS ======================================================================================== command, but can be changed using 'cluster-preferred-endpoint-type' config. This value is ========================================================================================= communicated along the clusterbus to all nodes, setting it to an empty string will remove ========================================================================================= the hostname and also propagate the removal. ============================================ cluster-announce-hostname "" ============================ Clusters can advertise how clients should connect to them using either their IP address, ======================================================================================== a user defined hostname, or by declaring they have no endpoint. Which endpoint is ================================================================================= shown as the preferred endpoint is set by using the cluster-preferred-endpoint-type =================================================================================== config with values 'ip', 'hostname', or 'unknown-endpoint'. This value controls how =================================================================================== the endpoint returned for MOVED/ASKING requests as well as the first field of CLUSTER SLOTS. ============================================================================================ If the preferred endpoint type is set to hostname, but no announced hostname is set, a '?' ========================================================================================== will be returned instead. ========================= When a cluster advertises itself as having an unknown endpoint, it's indicating that ==================================================================================== the server doesn't know how clients can reach the cluster. This can happen in certain ===================================================================================== networking situations where there are multiple possible routes to the node, and the =================================================================================== server doesn't know which one the client took. In this case, the server is expecting ==================================================================================== the client to reach out on the same endpoint it used for making the last request, but use ========================================================================================= the port provided in the response. ================================== cluster-preferred-endpoint-type ip ================================== In order to setup your cluster make sure to read the documentation ================================================================== available at https://redis.io web site. ======================================= ########################## CLUSTER DOCKER/NAT support ######################## In certain deployments, Redis Cluster nodes address discovery fails, because ============================================================================ addresses are NAT-ted or because ports are forwarded (the typical case is ========================================================================= Docker and other containers). ============================= In order to make Redis Cluster working in such environments, a static ===================================================================== configuration where each node knows its public address is needed. The ===================================================================== following four options are used for this scope, and are: ======================================================== \* cluster-announce-ip ====================== \* cluster-announce-port ======================== \* cluster-announce-tls-port ============================ \* cluster-announce-bus-port ============================ Each instructs the node about its address, client ports (for connections ======================================================================== without and with TLS) and cluster message bus port. The information is then =========================================================================== published in the header of the bus packets so that other nodes will be able to ============================================================================== correctly map the address of the node publishing the information. ================================================================= If cluster-tls is set to yes and cluster-announce-tls-port is omitted or set ============================================================================ to zero, then cluster-announce-port refers to the TLS port. Note also that ========================================================================== cluster-announce-tls-port has no effect if cluster-tls is set to no. ==================================================================== If the above options are not used, the normal Redis Cluster auto-detection ========================================================================== will be used instead. ===================== Note that when remapped, the bus port may not be at the fixed offset of ======================================================================= clients port + 10000, so you can specify any port and bus-port depending ======================================================================== on how they get remapped. If the bus-port is not set, a fixed offset of ======================================================================= 10000 will be used as usual. ============================ Example: ======== cluster-announce-ip 10.1.1.5 ============================ cluster-announce-tls-port 6379 ============================== cluster-announce-port 0 ======================= cluster-announce-bus-port 6380 ============================== ################################## SLOW LOG ################################### The Redis Slow Log is a system to log queries that exceeded a specified ======================================================================= execution time. The execution time does not include the I/O operations ====================================================================== like talking with the client, sending the reply and so forth, ============================================================= but just the time needed to actually execute the command (this is the only ========================================================================== stage of command execution where the thread is blocked and can not serve ======================================================================== other requests in the meantime). ================================ You can configure the slow log with two parameters: one tells Redis =================================================================== what is the execution time, in microseconds, to exceed in order for the ======================================================================= command to get logged, and the other parameter is the length of the =================================================================== slow log. When a new command is logged the oldest one is removed from the ========================================================================= queue of logged commands. ========================= The following time is expressed in microseconds, so 1000000 is equivalent ========================================================================= to one second. Note that a negative number disables the slow log, while ======================================================================= a value of zero forces the logging of every command. ==================================================== slowlog-log-slower-than 10000 There is no limit to this length. Just be aware that it will consume memory. ============================================================================ You can reclaim memory used by the slow log with SLOWLOG RESET. =============================================================== slowlog-max-len 128 ################################ LATENCY MONITOR ############################## The Redis latency monitoring subsystem samples different operations =================================================================== at runtime in order to collect data related to possible sources of ================================================================== latency of a Redis instance. ============================ Via the LATENCY command this information is available to the user that can ========================================================================== print graphs and obtain reports. ================================ The system only logs operations that were performed in a time equal or ====================================================================== greater than the amount of milliseconds specified via the ========================================================= latency-monitor-threshold configuration directive. When its value is set ======================================================================== to zero, the latency monitor is turned off. =========================================== By default latency monitoring is disabled since it is mostly not needed ======================================================================= if you don't have latency issues, and collecting data has a performance ======================================================================= impact, that while very small, can be measured under big load. Latency ====================================================================== monitoring can easily be enabled at runtime using the command ============================================================= "CONFIG SET latency-monitor-threshold \<milliseconds\>" if needed. ================================================================== latency-monitor-threshold 0 ################################ LATENCY TRACKING ############################## The Redis extended latency monitoring tracks the per command latencies and enables ================================================================================== exporting the percentile distribution via the INFO latencystats command, ======================================================================== and cumulative latency distributions (histograms) via the LATENCY command. ========================================================================== By default, the extended latency monitoring is enabled since the overhead ========================================================================= of keeping track of the command latency is very small. ====================================================== latency-tracking yes ==================== By default the exported latency percentiles via the INFO latencystats command ============================================================================= are the p50, p99, and p999. =========================== latency-tracking-info-percentiles 50 99 99.9 ============================================ ############################# EVENT NOTIFICATION ############################## Redis can notify Pub/Sub clients about events happening in the key space. ========================================================================= This feature is documented at https://redis.io/topics/notifications =================================================================== For instance if keyspace events notification is enabled, and a client ===================================================================== performs a DEL operation on key "foo" stored in the Database 0, two =================================================================== messages will be published via Pub/Sub: ======================================= PUBLISH **keyspace@0**:foo del ============================== PUBLISH **keyevent@0**:del foo ============================== It is possible to select the events that Redis will notify among a set ====================================================================== of classes. Every class is identified by a single character: ============================================================ K Keyspace events, published with **keyspace@\<db\>** prefix. ============================================================= E Keyevent events, published with **keyevent@\<db\>** prefix. ============================================================= g Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ... ==================================================================== $ String commands ================= l List commands =============== s Set commands ============== h Hash commands =============== z Sorted set commands ===================== x Expired events (events generated every time a key expires) ============================================================ e Evicted events (events generated when a key is evicted for maxmemory) ======================================================================= n New key events (Note: not included in the 'A' class) ====================================================== t Stream commands ================= d Module key type events ======================== m Key-miss events (Note: It is not included in the 'A' class) ============================================================= A Alias for g$lshzxetd, so that the "AKE" string means all the events ===================================================================== (Except key-miss events which are excluded from 'A' due to their ================================================================ unique nature). =============== The "notify-keyspace-events" takes as argument a string that is composed ======================================================================== of zero or multiple characters. The empty string means that notifications ========================================================================= are disabled. ============= Example: to enable list and generic events, from the point of view of the ========================================================================= event name, use: ================ notify-keyspace-events Elg ========================== Example 2: to get the stream of the expired keys subscribing to channel ======================================================================= name **keyevent@0**:expired use: ================================ notify-keyspace-events Ex ========================= By default all notifications are disabled because most users don't need ======================================================================= this feature and the feature has some overhead. Note that if you don't ====================================================================== specify at least one of K or E, no events will be delivered. ============================================================ notify-keyspace-events "" ############################### ADVANCED CONFIG ############################### Hashes are encoded using a memory efficient data structure when they have a =========================================================================== small number of entries, and the biggest entry does not exceed a given ====================================================================== threshold. These thresholds can be configured using the following directives. ============================================================================= hash-max-listpack-entries 512 hash-max-listpack-value 64 Lists are also encoded in a special way to save a lot of space. =============================================================== The number of entries allowed per internal list node can be specified ===================================================================== as a fixed maximum size or a maximum number of elements. ======================================================== For a fixed maximum size, use -5 through -1, meaning: ===================================================== -5: max size: 64 Kb \<-- not recommended for normal workloads ============================================================= -4: max size: 32 Kb \<-- not recommended ======================================== -3: max size: 16 Kb \<-- probably not recommended ================================================= -2: max size: 8 Kb \<-- good ============================ -1: max size: 4 Kb \<-- good ============================ Positive numbers mean store up to *exactly* that number of elements =================================================================== per list node. ============== The highest performing option is usually -2 (8 Kb size) or -1 (4 Kb size), ========================================================================== but if your use case is unique, adjust the settings as necessary. ================================================================= list-max-listpack-size -2 Lists may also be compressed. ============================= Compress depth is the number of quicklist ziplist nodes from *each* side of =========================================================================== the list to *exclude* from compression. The head and tail of the list ===================================================================== are always uncompressed for fast push/pop operations. Settings are: =================================================================== 0: disable all list compression =============================== 1: depth 1 means "don't start compressing until after 1 node into the list, =========================================================================== going from either the head or tail" =================================== So: \[head\]-\>node-\>node-\>...-\>node-\>\[tail\] ================================================== \[head\], \[tail\] will always be uncompressed; inner nodes will compress. ========================================================================== 2: \[head\]-\>\[next\]-\>node-\>node-\>...-\>node-\>\[prev\]-\>\[tail\] ======================================================================= 2 here means: don't compress head or head-\>next or tail-\>prev or tail, ======================================================================== but compress all nodes between them. ==================================== 3: \[head\]-\>\[next\]-\>\[next\]-\>node-\>node-\>...-\>node-\>\[prev\]-\>\[prev\]-\>\[tail\] ============================================================================================= etc. ==== list-compress-depth 0 Sets have a special encoding in just one case: when a set is composed ===================================================================== of just strings that happen to be integers in radix 10 in the range =================================================================== of 64 bit signed integers. ========================== The following configuration setting sets the limit in the size of the ===================================================================== set in order to use this special memory saving encoding. ======================================================== set-max-intset-entries 512 Similarly to hashes and lists, sorted sets are also specially encoded in ======================================================================== order to save a lot of space. This encoding is only used when the length and ============================================================================ elements of a sorted set are below the following limits: ======================================================== zset-max-listpack-entries 128 zset-max-listpack-value 64 HyperLogLog sparse representation bytes limit. The limit includes the ===================================================================== 16 bytes header. When an HyperLogLog using the sparse representation crosses ============================================================================ this limit, it is converted into the dense representation. ========================================================== A value greater than 16000 is totally useless, since at that point the ====================================================================== dense representation is more memory efficient. ============================================== The suggested value is \~ 3000 in order to have the benefits of =============================================================== the space efficient encoding without slowing down too much PFADD, ================================================================= which is O(N) with the sparse encoding. The value can be raised to ================================================================== \~ 10000 when CPU is not a concern, but space is, and the data set is ===================================================================== composed of many HyperLogLogs with cardinality in the 0 - 15000 range. ====================================================================== hll-sparse-max-bytes 3000 Streams macro node max size / items. The stream data structure is a radix ========================================================================= tree of big nodes that encode multiple items inside. Using this configuration ============================================================================= it is possible to configure how big a single node can be in bytes, and the ========================================================================== maximum number of items it may contain before switching to a new node when ========================================================================== appending new stream entries. If any of the following settings are set to ========================================================================= zero, the limit is ignored, so for instance it is possible to set just a ======================================================================== max entries limit by setting max-bytes to 0 and max-entries to the desired ========================================================================== value. ====== stream-node-max-bytes 4096 stream-node-max-entries 100 Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in ========================================================================= order to help rehashing the main Redis hash table (the one mapping top-level ============================================================================ keys to values). The hash table implementation Redis uses (see dict.c) ====================================================================== performs a lazy rehashing: the more operation you run into a hash table ======================================================================= that is rehashing, the more rehashing "steps" are performed, so if the ====================================================================== server is idle the rehashing is never complete and some more memory is used =========================================================================== by the hash table. ================== The default is to use this millisecond 10 times every second in order to ======================================================================== actively rehash the main dictionaries, freeing memory when possible. ==================================================================== If unsure: ========== use "activerehashing no" if you have hard latency requirements and it is ======================================================================== not a good thing in your environment that Redis can reply from time to time =========================================================================== to queries with 2 milliseconds delay. ===================================== use "activerehashing yes" if you don't have such hard requirements but ====================================================================== want to free memory asap when possible. ======================================= activerehashing yes The client output buffer limits can be used to force disconnection of clients ============================================================================= that are not reading data from the server fast enough for some reason (a ======================================================================== common reason is that a Pub/Sub client can't consume messages as fast as the ============================================================================ publisher can produce them). ============================ The limit can be set differently for the three different classes of clients: ============================================================================ normal -\> normal clients including MONITOR clients =================================================== replica -\> replica clients =========================== pubsub -\> clients subscribed to at least one pubsub channel or pattern ======================================================================= The syntax of every client-output-buffer-limit directive is the following: ========================================================================== client-output-buffer-limit \<class\> \<hard limit\> \<soft limit\> \<soft seconds\> =================================================================================== A client is immediately disconnected once the hard limit is reached, or if ========================================================================== the soft limit is reached and remains reached for the specified number of ========================================================================= seconds (continuously). ======================= So for instance if the hard limit is 32 megabytes and the soft limit is ======================================================================= 16 megabytes / 10 seconds, the client will get disconnected immediately ======================================================================= if the size of the output buffers reach 32 megabytes, but will also get ======================================================================= disconnected if the client reaches 16 megabytes and continuously overcomes ========================================================================== the limit for 10 seconds. ========================= By default normal clients are not limited because they don't receive data ========================================================================= without asking (in a push way), but just after a request, so only ================================================================= asynchronous clients may create a scenario where data is requested faster ========================================================================= than it can read. ================= Instead there is a default limit for pubsub and replica clients, since ====================================================================== subscribers and replicas receive data in a push fashion. ======================================================== Note that it doesn't make sense to set the replica clients output buffer ======================================================================== limit lower than the repl-backlog-size config (partial sync will succeed ======================================================================== and then replica will get disconnected). ======================================== Such a configuration is ignored (the size of repl-backlog-size will be used). ============================================================================= This doesn't have memory consumption implications since the replica client ========================================================================== will share the backlog buffers memory. ====================================== Both the hard or the soft limit can be disabled by setting them to zero. ======================================================================== client-output-buffer-limit normal 0 0 0 client-output-buffer-limit replica 256mb 64mb 60 client-output-buffer-limit pubsub 32mb 8mb 60 Client query buffers accumulate new commands. They are limited to a fixed ========================================================================= amount by default in order to avoid that a protocol desynchronization (for ========================================================================== instance due to a bug in the client) will lead to unbound memory usage in ========================================================================= the query buffer. However you can configure it here if you have very special ============================================================================ needs, such us huge multi/exec requests or alike. ================================================= client-query-buffer-limit 1gb ============================= In some scenarios client connections can hog up memory leading to OOM ===================================================================== errors or data eviction. To avoid this we can cap the accumulated memory ======================================================================== used by all client connections (all pubsub and normal clients). Once we ======================================================================= reach that limit connections will be dropped by the server freeing up ===================================================================== memory. The server will attempt to drop the connections using the most ====================================================================== memory first. We call this mechanism "client eviction". ======================================================= Client eviction is configured using the maxmemory-clients setting as follows: ============================================================================= 0 - client eviction is disabled (default) ========================================= A memory value can be used for the client eviction threshold, ============================================================= for example: ============ maxmemory-clients 1g ==================== A percentage value (between 1% and 100%) means the client eviction threshold ============================================================================ is based on a percentage of the maxmemory setting. For example to set client ============================================================================ eviction at 5% of maxmemory: ============================ maxmemory-clients 5% ==================== In the Redis protocol, bulk requests, that are, elements representing single ============================================================================ strings, are normally limited to 512 mb. However you can change this limit ========================================================================== here, but must be 1mb or greater ================================ proto-max-bulk-len 512mb ======================== Redis calls an internal function to perform many background tasks, like ======================================================================= closing connections of clients in timeout, purging expired keys that are ======================================================================== never requested, and so forth. ============================== Not all tasks are performed with the same frequency, but Redis checks for ========================================================================= tasks to perform according to the specified "hz" value. ======================================================= By default "hz" is set to 10. Raising the value will use more CPU when ====================================================================== Redis is idle, but at the same time will make Redis more responsive when ======================================================================== there are many keys expiring at the same time, and timeouts may be ================================================================== handled with more precision. ============================ The range is between 1 and 500, however a value over 100 is usually not ======================================================================= a good idea. Most users should use the default of 10 and raise this up to ========================================================================= 100 only in environments where very low latency is required. ============================================================ hz 10 Normally it is useful to have an HZ value which is proportional to the ====================================================================== number of clients connected. This is useful in order, for instance, to ====================================================================== avoid too many clients are processed for each background task invocation ======================================================================== in order to avoid latency spikes. ================================= Since the default HZ value by default is conservatively set to 10, Redis ======================================================================== offers, and enables by default, the ability to use an adaptive HZ value ======================================================================= which will temporarily raise when there are many connected clients. =================================================================== When dynamic HZ is enabled, the actual configured HZ will be used ================================================================= as a baseline, but multiples of the configured HZ value will be actually ======================================================================== used as needed once more clients are connected. In this way an idle =================================================================== instance will use very little CPU time while a busy instance will be ==================================================================== more responsive. ================ dynamic-hz yes When a child rewrites the AOF file, if the following option is enabled ====================================================================== the file will be fsync-ed every 4 MB of data generated. This is useful ====================================================================== in order to commit the file to the disk more incrementally and avoid ==================================================================== big latency spikes. =================== aof-rewrite-incremental-fsync yes When redis saves RDB file, if the following option is enabled ============================================================= the file will be fsync-ed every 4 MB of data generated. This is useful ====================================================================== in order to commit the file to the disk more incrementally and avoid ==================================================================== big latency spikes. =================== rdb-save-incremental-fsync yes Redis LFU eviction (see maxmemory setting) can be tuned. However it is a good ============================================================================= idea to start with the default settings and only change them after investigating ================================================================================ how to improve the performances and how the keys LFU change over time, which ============================================================================ is possible to inspect via the OBJECT FREQ command. =================================================== There are two tunable parameters in the Redis LFU implementation: the ===================================================================== counter logarithm factor and the counter decay time. It is important to ======================================================================= understand what the two parameters mean before changing them. ============================================================= The LFU counter is just 8 bits per key, it's maximum value is 255, so Redis =========================================================================== uses a probabilistic increment with logarithmic behavior. Given the value ========================================================================= of the old counter, when a key is accessed, the counter is incremented in ========================================================================= this way: ========= 1. A random number R between 0 and 1 is extracted. ================================================== 2. A probability P is calculated as 1/(old_value\*lfu_log_factor+1). ==================================================================== 3. The counter is incremented only if R \< P. ============================================= The default lfu-log-factor is 10. This is a table of how the frequency ====================================================================== counter changes with a different number of accesses with different ================================================================== logarithmic factors: ==================== +--------+------------+------------+------------+------------+------------+ =========================================================================== \| factor \| 100 hits \| 1000 hits \| 100K hits \| 1M hits \| 10M hits \| ========================================================================= +--------+------------+------------+------------+------------+------------+ =========================================================================== \| 0 \| 104 \| 255 \| 255 \| 255 \| 255 \| ========================================== +--------+------------+------------+------------+------------+------------+ =========================================================================== \| 1 \| 18 \| 49 \| 255 \| 255 \| 255 \| ======================================== +--------+------------+------------+------------+------------+------------+ =========================================================================== \| 10 \| 10 \| 18 \| 142 \| 255 \| 255 \| ========================================= +--------+------------+------------+------------+------------+------------+ =========================================================================== \| 100 \| 8 \| 11 \| 49 \| 143 \| 255 \| ======================================== +--------+------------+------------+------------+------------+------------+ =========================================================================== NOTE: The above table was obtained by running the following commands: ===================================================================== redis-benchmark -n 1000000 incr foo =================================== redis-cli object freq foo ========================= NOTE 2: The counter initial value is 5 in order to give new objects a chance ============================================================================ to accumulate hits. =================== The counter decay time is the time, in minutes, that must elapse in order ========================================================================= for the key counter to be divided by two (or decremented if it has a value ========================================================================== less \<= 10). ============= The default value for the lfu-decay-time is 1. A special value of 0 means to ============================================================================ decay the counter every time it happens to be scanned. ====================================================== lfu-log-factor 10 ================= lfu-decay-time 1 ================ ########################### ACTIVE DEFRAGMENTATION ####################### What is active defragmentation? =============================== ------------------------------- =============================== Active (online) defragmentation allows a Redis server to compact the ==================================================================== spaces left between small allocations and deallocations of data in memory, ========================================================================== thus allowing to reclaim back memory. ===================================== Fragmentation is a natural process that happens with every allocator (but ========================================================================= less so with Jemalloc, fortunately) and certain workloads. Normally a server ============================================================================ restart is needed in order to lower the fragmentation, or at least to flush =========================================================================== away all the data and create it again. However thanks to this feature ===================================================================== implemented by Oran Agra for Redis 4.0 this process can happen at runtime ========================================================================= in a "hot" way, while the server is running. ============================================ Basically when the fragmentation is over a certain level (see the ================================================================= configuration options below) Redis will start to create new copies of the ========================================================================= values in contiguous memory regions by exploiting certain specific Jemalloc =========================================================================== features (in order to understand if an allocation is causing fragmentation ========================================================================== and to allocate it in a better place), and at the same time, will release the ============================================================================= old copies of the data. This process, repeated incrementally for all the keys ============================================================================= will cause the fragmentation to drop back to normal values. =========================================================== Important things to understand: =============================== 1. This feature is disabled by default, and only works if you compiled Redis ============================================================================ to use the copy of Jemalloc we ship with the source code of Redis. ================================================================== This is the default with Linux builds. ====================================== 2. You never need to enable this feature if you don't have fragmentation ======================================================================== issues. ======= 3. Once you experience fragmentation, you can enable this feature when ====================================================================== needed with the command "CONFIG SET activedefrag yes". ====================================================== The configuration parameters are able to fine tune the behavior of the ====================================================================== defragmentation process. If you are not sure about what they mean it is ======================================================================= a good idea to leave the defaults untouched. ============================================ Active defragmentation is disabled by default ============================================= activedefrag no =============== Minimum amount of fragmentation waste to start active defrag ============================================================ active-defrag-ignore-bytes 100mb ================================ Minimum percentage of fragmentation to start active defrag ========================================================== active-defrag-threshold-lower 10 ================================ Maximum percentage of fragmentation at which we use maximum effort ================================================================== active-defrag-threshold-upper 100 ================================= Minimal effort for defrag in CPU percentage, to be used when the lower ====================================================================== threshold is reached ==================== active-defrag-cycle-min 1 ========================= Maximal effort for defrag in CPU percentage, to be used when the upper ====================================================================== threshold is reached ==================== active-defrag-cycle-max 25 ========================== Maximum number of set/hash/zset/list fields that will be processed from ======================================================================= the main dictionary scan ======================== active-defrag-max-scan-fields 1000 ================================== Jemalloc background thread for purging will be enabled by default ================================================================= jemalloc-bg-thread yes It is possible to pin different threads and processes of Redis to specific ========================================================================== CPUs in your system, in order to maximize the performances of the server. ========================================================================= This is useful both in order to pin different Redis threads in different ======================================================================== CPUs, but also in order to make sure that multiple Redis instances running ========================================================================== in the same host will be pinned to different CPUs. ================================================== Normally you can do this using the "taskset" command, however it is also ======================================================================== possible to this via Redis configuration directly, both in Linux and FreeBSD. ============================================================================= You can pin the server/IO threads, bio threads, aof rewrite child process, and ============================================================================== the bgsave child process. The syntax to specify the cpu list is the same as =========================================================================== the taskset command: ==================== Set redis server/io threads to cpu affinity 0,2,4,6: ==================================================== server_cpulist 0-7:2 ==================== Set bio threads to cpu affinity 1,3: ==================================== bio_cpulist 1,3 =============== Set aof rewrite child process to cpu affinity 8,9,10,11: ======================================================== aof_rewrite_cpulist 8-11 ======================== Set bgsave child process to cpu affinity 1,10,11 ================================================ bgsave_cpulist 1,10-11 ====================== In some cases redis will emit warnings and even refuse to start if it detects ============================================================================= that the system is in bad state, it is possible to suppress these warnings ========================================================================== by setting the following config which takes a space delimited list of warnings ============================================================================== to suppress =========== ignore-warnings ARM64-COW-BUG ============================= Redis configuration rewrite by 1Panel ===================================== `End Redis configuration rewrite by 1Panel`最后把保存好的配置文件上传至刚创建好的docker映射文件夹内。
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打开"Container Manager"，在"项目"中，点击"新增"。填写项目名称，路径选择创建好的映射文件夹，文件选择"创建 docker-compose.yml",然后将以下配置代码复制粘贴进去。
version: '3' services: redis: image: redis:latest container_name: redis ports: # 映射本地端口 - "6379:6379" volumes: # 映射数据文件夹 - ./data:/data # 映射配置文件redis.conf - ./data/redis.conf:/etc/redis/redis.conf # 映射日志文件夹 - ./data/log:/logs command: redis-server --requirepass p@ssw0rd --save 60 1 --loglevel warning restart: on-failure装载路径说明
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/etc/redis/redis.conf：此为文件映射，必须选择到文件而不能是文件夹； -
/data：持久化存储的数据文件位置； -
/logs：日志文件位置。
执行命令说明
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redis-server：启动服务用，不可删除； -
--requirepass {password}：添加此命令设置密码，建议使用复杂密码，请将{password}替换成你的密码； -
--save 60 1：有几种不同的持久性策略可供选择。如果至少执行了 1 次写入操作，则此操作将每 60 秒保存一次数据库快照（这也将导致更多日志，因此该选项可能是可取的），可选； -
--loglevel warning：日志级别，可选。
最后点击"下一步"，等待镜像拉取和容器创建完成。
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