文章目录
- 一、概述
- 二、觉见基础配置
- 1.1 导入另一个配置文件
- 1.2 添加Redis扩展
- 1.3 绑定Redis服务在那些网卡上，也就是远程可以通过那个的IP地址访问。
- 1.2 指定Redis服务监听端口
- 1.2 最大分配内容大小
- 1.2 后台服务方式运行
- 1.2 日志记录文件
- 1.2 添加扩展
- 三、完整配置文件 redis.conf
如果您还不会安装Redis请看这。
一、概述
-
Redis（Remote Dictionary Server）是一种高性能的开源内存数据库，它具有多种用途和功能，可以充当缓存、消息队列、数据库、实时分析和数据处理平台等多种角色。Redis常见配置项下：
-
网络和安全设置
- 设置绑定地址（bind）以控制 Redis 监听的网络接口。
- 配置端口号（port）以指定 Redis 服务器监听的端口。
- 可以使用密码（requirepass）来保护 Redis 服务器，限制访问权限。
-
持久化设置
- 可以选择使用快照持久化（RDB）或追加文件持久化（AOF）来将数据保存到磁盘上。
- 配置持久化文件的路径和文件名。
- 可以设置自动触发持久化的条件，如时间间隔或写操作数。
-
内存优化
- 配置最大使用内存量（maxmemory）以限制 Redis 的内存使用。
- 可以设置内存淘汰策略（maxmemory-policy）来决定在达到最大内存限制时如何处理数据。
-
客户端设置
- 配置最大客户端连接数（maxclients）以限制同时连接到 Redis 的客户端数量。
- 可以设置超时时间（timeout）以控制客户端的空闲连接时间。
-
日志记录和诊断
- 配置日志级别（loglevel）来控制日志的详细程度。
- 可以指定日志文件的路径和文件名。
- 可以启用慢查询日志（slowlog），记录执行时间超过阈值的命令。
-
主从复制和集群设置
- 配置主从复制（replication）以设置 Redis 实例之间的主从关系。
- 可以设置集群模式（cluster-enabled）以支持 Redis 集群。
-
性能调优
- 可以配置线程数和 CPU 核心绑定，以优化后台线程的性能。
- 配置合适的最大客户端连接数、内存限制和持久化设置，以满足系统需求。
-
安全性
- 配置密码（requirepass）以限制对 Redis 服务器的访问。
- 可以使用防火墙和网络隔离等措施来保护 Redis 的网络访问。
二、觉见基础配置
1.1 导入另一个配置文件
include /path/to/local.conf
1.2 添加Redis扩展
loadmodule /path/to/my_module.so
1.3 绑定Redis服务在那些网卡上，也就是远程可以通过那个的IP地址访问。
bind 127.0.0.1
1.2 指定Redis服务监听端口
port 6379
1.2 最大分配内容大小
- 设置内存最大大小为4G
maxmemory 4gb
1.2 后台服务方式运行
- 是否以后台服务方式运行，no表示以前面阻塞方式运行
daemonize no
1.2 日志记录文件
- 开启后会将日志记录到文件，不会在屏幕上打印（一般以服务方式运行时打开）
logfile "/var/log/redis_6379.log"
1.2 添加扩展
loadmodule /path/to/my_module.so
三、完整配置文件 redis.conf
# 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.
#
# Notice 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.
#
# 导入Redis另一个配置文件，一般放在配置文件开头
# 例如你要配置多个Redis实例时，可以把相同部分抽取出来放一个共同的配置文件中
# 然后在单独的配置文件中配置不同的部分，再使用下面的命令导入相同的部分。
# include /path/to/local.conf
# include /path/to/other.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.
#
# 如果添加第三方或自己实现的扩展库，则使用以下命令（注意：Windows上*.dll文件，Linux是*.so文件）。
# 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 the network interfaces available on the server.
# It is possible to listen to just one or multiple selected interfaces using
# the "bind" configuration directive, followed by one or more IP addresses.
#
# Examples:
#
# 绑定Redis服务在那些网卡上，也就是远程可以通过那个的IP地址访问。
# bind 192.168.1.100 10.0.0.1
# bind 127.0.0.1 ::1
#
# ~~~ 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 into
# the IPv4 loopback interface address (this means Redis will be able to
# accept connections only from clients running into the same computer it
# is running).
#
# IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
# JUST COMMENT THE FOLLOWING LINE.
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
bind 127.0.0.1
# 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 if:
#
# 1) The server is not binding explicitly to a set of addresses using the
# "bind" directive.
# 2) No password is configured.
#
# The server only accepts connections from clients connecting from the
# IPv4 and IPv6 loopback addresses 127.0.0.1 and ::1, and from 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, nor a specific set of interfaces
# are explicitly listed using the "bind" directive.
# 是否开启安全机制，即保护模式
# 如果配置为yes，当服务器未显式使用 "bind" 指令绑定到一组地址时 或 没有配置密码（没有启用认证机制） 时保护模式生效。
# 保护模式生效后，只接受来自本地主机的套接字的连接请求。也就是其他主机无法访问。
protected-mode yes
# Accept connections on the specified port, default is 6379 (IANA #815344).
# If port 0 is specified Redis will not listen on a TCP socket.
# Redis 服务监听端口
port 6379
# TCP listen() backlog.
#
# In high requests-per-second environments you need an high backlog in order
# to avoid slow clients connections 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.
# 服务器能够同时排队等待的客户端连接请求个数，超过这个数的请求会被气拒绝。
# 在Linux中，超过/proc/sys/net/core/somaxconn的值也无效。 这里配置了511个。
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.
#
# 指定 Redis 服务器监听的 Unix 套接字的路径
# 如果启用了这个配置，并指定了套接字路径，Redis 将通过 Unix 套接字来接受客户端连接，而不是通过网络端口。
# 这对于本地通信和与其他进程之间的通信非常有用。
# unixsocket /tmp/redis.sock
# 设置 Unix 套接字文件权限的配置
# 这里设置为700，表示只有拥有者（通常是 Redis 进程的运行用户）具有读、写和执行权限，其他无权限
# unixsocketperm 700
# Close the connection after a client is idle for N seconds (0 to disable)
# 客户端连接的空闲超时时间。
# 在这里，将超时设置为 0，表示客户端连接永不超时，即不会主动关闭任何空闲的客户端连接。
# 如果设置为非零值，表示客户端连接在空闲指定秒数后将被服务器自动关闭。
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) Take the connection alive from the point of view of network
# equipment in the middle.
#
# 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.
# 保持TCP连接活跃的机制的配置
# 这里配置300，表示系统将每隔 300 秒发送一个TCP ACK（确认）以保持连接活跃
tcp-keepalive 300
################################# 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:
#
# 关闭默认的非加密端口
# port 0
# 将 TLS 端口设置为 6379， 表示监听 6379 端口，并且使用 TLS/SSL 进行加密通信
# 注意：如果使用加密通信，那么下面的证书和公钥一定要配置才有效。
# 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.
#
# 用于加密通信的证书
# tls-cert-file redis.crt
# 且于加密通信的公钥
# tls-key-file redis.key
# Configure a DH parameters file to enable Diffie-Hellman (DH) key exchange:
#
# 配置 Diffie-Hellman 密钥交换所需的参数文件
# 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.
#
# 配置CA的证书文件
# tls-ca-cert-file ca.crt
# 配置CA的证书目录
# 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.
#
# It is possible to disable authentication using this directive.
#
# 是否启用 客户端（包括副本服务器）连接到 TLS 端口时必须使用有效的客户端证书进行身份验证
# tls-auth-clients no
# 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.
#
# 是否启用 主服务器和副本之间的通信加密
# 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:
# 是否启用 群集之间通信加密
# tls-cluster yes
# 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:
# 指定TLS协议版本
# 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.
# 这个配置表示在 TLSv1.2 及以下版本中，设置允许的密码套件（ciphers）。
# "DEFAULT:!MEDIUM" 是一个密码套件字符串，用于指定可接受的密码套件范围。
# 其中，"DEFAULT" 表示使用默认的密码套件列表。"!MEDIUM" 表示不包括中等强度的密码套件。
# 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.
# 这个配置表示设置允许的 TLSv1.3 密码套件（ciphersuites）。
# "TLS_CHACHA20_POLY1305_SHA256" 是一个密码套件名称，用于指定在 TLSv1.3 中可接受的密码套件。
# 这个密码套件使用了 ChaCha20 密码流加密算法和 Poly1305 消息认证码算法，并通过 SHA-256 哈希算法实现完整性保护。该密码套件提供了高安全性和性能。
# 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.
# 这个配置表示在选择密码套件时，使用服务器的优先级而不是客户端的优先级。默认情况下，服务器遵循客户端的优先级。
# 当设置为 "yes" 时，服务器将优先选择自己支持的密码套件，而不是遵循客户端提供的优先级顺序。
# 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.
# 是否禁用 TLS 会话缓存。默认情况下，TLS 会话缓存是启用的，以便支持它的客户端可以更快、更便宜地重新连接。
# 设置为 "no"，可以禁用缓存，从而阻止客户端重用缓存的会话信息。
# 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.
# 修改默认的 TLS 会话缓存大小。指定的值表示缓存的会话数量。如果设置为零，则表示缓存大小无限制。默认大小是 20480。
# tls-session-cache-size 5000
# Change the default timeout of cached TLS sessions. The default timeout is 300
# seconds.
# 修改默认的缓存的 TLS 会话超时时间。指定的值表示会话在缓存中的存活时间，以秒为单位。默认超时时间是 300 秒。
# 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.
# 是否以后台服务方式运行，no表示以前面阻塞方式运行
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
# supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET
# 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 liveness pings back to your supervisor.
# 是否与程监控程序（supervisor）进行交互
# 设置为 no 时，Redis 将以独立的进程运行，不会与任何进程监控程序进行通信。
# 表示不会受到监控程序的启动、停止或重启等操作的影响。Redis 进程将完全由操作系统管理，而不会与外部程序进行交互或接收信号。
supervised no
# 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.
# 指定 PID 文件的路径和名称
# 当 Redis 以非守护进程方式运行时，如果没有在配置中指定 PID 文件，则不会创建 PID 文件。
# 当 Redis 以守护进程方式运行时，默认情况下会创建一个 PID 文件，路径为 "/var/run/redis.pid"。
# 这里手动指定了新路径
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)
# 配置日志级别，有debug、verbose、notice、warning可选
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
# 配置日志文件存放路径
# 这里没有配置，意思是将日志输出到标准输出（stdout）。
# 注意：如果 Redis 以守护进程方式运行，并且日志输出被设置为标准输出，日志将被发送到 "/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.
# 是否将日志发送到系统日志记录器
# syslog-enabled no
# Specify the syslog identity.
# 发送到系统日志记录器里的标识
# syslog-ident redis
# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
# 指定 Redis 日志在系统日志中的设施（facility）。
# 设施是系统日志中的一个分类，用于标识日志消息的来源或类型。
# 可以选择的设施包括 USER 和 LOCAL0-LOCAL7
# syslog-facility local0
# 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
# Redis默认库数量，系统默认16个，取值范围0~15。
# 在连接时可以使用-n参数指定。连接后可以使用select命令切换
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. 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.
# 启动日志中是否显示 ASCII 艺术品（logo）
always-show-logo yes
################################ SNAPSHOTTING ################################
#
# Save the DB on disk:
#
# save <seconds> <changes>
#
# Will save the DB if both the given number of seconds and the given
# number of write operations against the DB occurred.
#
# In the example below the behaviour will be to save:
# after 900 sec (15 min) if at least 1 key changed
# after 300 sec (5 min) if at least 10 keys changed
# after 60 sec if at least 10000 keys changed
#
# Note: you can disable saving completely by commenting out all "save" lines.
#
# It is also possible to remove all the previously configured save
# points by adding a save directive with a single empty string argument
# like in the following example:
#
# save ""
# Redis RDB持久化策略。
# 这里表示当时间超过900秒且至少有1个key变化时触发RDB持久化
save 900 1
# 这里表示当时间超过300秒且至少有10个key变化时触发RDB持久化
save 300 10
# 这里表示当时间超过60秒且至少有10000个key变化时触发RDB持久化
save 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.
# 是否在执行后台保存（bgsave）操作时出现错误时，停止对数据进行写入操作
stop-writes-on-bgsave-error yes
# Compress string objects using LZF when dump .rdb databases?
# For default that's set to 'yes' 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.
# Redis RDB持久化时，是否开启压缩
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.
# Redis RDB持久化时，是否写入校验位
rdbchecksum yes
# The filename where to dump the DB
# Redis RDB持久化 文件名
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持久化方式下，删除数据时，是否以同步方式删除数据文件
# 这里配置为否，表示Redis删除时不会阻塞，而是以异步方式删除。之可能会导致数据不一致。
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.
# Redis RDB持久化 文件目录，这里表示Redis安装目录
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.
# 主从复制模式中，从节点加入主节点的配置方式，如replicaof 127.0.0.1 6379
# 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.
#
# 设置 Redis 主节点与从节点之间的身份验证密码
# 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:
# 设置用户名，注意6.0以前不支持
# 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
# an error "SYNC with master in progress" to all the kind of commands
# but to INFO, replicaOF, AUTH, PING, SHUTDOWN, REPLCONF, ROLE, CONFIG,
# SUBSCRIBE, UNSUBSCRIBE, PSUBSCRIBE, PUNSUBSCRIBE, PUBLISH, PUBSUB,
# COMMAND, POST, HOST: and LATENCY.
# 在主从复制模式中，在从机同步主机数据过程中，是否暴露原数据。
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.
# 在主从复制模式中，从机是否为只读模式
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.
# 在主从复制模式中，主机向从机同步数据时，是否直接通过网络发送，而不是先在磁盘建立RDB然后再同步。
# 也就是yes就是直接从网络发，no就是先存磁盘，然后再发
repl-diskless-sync no
# 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.
# 从节点在进行无磁盘同步（diskless sync）时的延迟时间
repl-diskless-sync-delay 5
# -----------------------------------------------------------------------------
# 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 your do 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
# recived 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 salve 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 a copy of the current db contents in RAM while parsing
# the data directly from the socket. note that this requires
# sufficient memory, if you don't have it, you risk an OOM kill.
# 是否禁用 Redis 的无磁盘加载（diskless load）功能
repl-diskless-load disabled
# Replicas send PINGs to server 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.
#
# 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.
# 复制机制中的 TCP 连接 是否禁用 TCP_NODELAY 选项。
# TCP_NODELAY 是一个 TCP 协议的选项，用于控制数据包的延迟和带宽利用率。
# 设置为no，表示在复制过程中，数据包将尽可能快地发送，以减少延迟。
# 这对于实时性要求较高的应用场景可能很重要，因为它可以减少数据传输的延迟，并保持较低的通信延迟。
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 time the replica can be
# disconnected and later be able to perform a partial resynchronization.
#
# The backlog is only allocated once there is at least a replica connected.
# 在主从复制模式中，复制的缓存区大小。
# 太小可能会因为从机无法追赶上主服务的操作而导致复制延迟。太大又会占用更多空间
# repl-backlog-size 1mb
# After a master has no longer 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 the replicas: hence they should always accumulate backlog.
#
# A value of 0 means to never release the backlog.
# 设置从节点复制后备日志的最大存活时间为
# 3600表示如果一个从节点在1小时内没有连接到主节点，它将丢失之前的复制日志，并且在重新连接时将无法进行部分复制。
# 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.
# 用于设置数据库中特定数据副本的优先级。
# 在数据同步和访问时，具有优先级100的副本将被视为最高优先级，可能会被优先选择用于读取或写入操作。
replica-priority 100
# 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:
#
# 设置在执行写操作之前，Sentinel要求的最少副本数量。
# 例如，如果你将 min-replicas-to-write 设置为3，那么在执行写操作之前，至少需要有3个从服务器（副本）是可用的，以确保数据的高可用性和一致性。
# 如果可用的从服务器数量低于配置的值，写操作将被拒绝，以确保数据的完整性。
# min-replicas-to-write 3
# 设置从服务器的最大复制延迟。
# 例如，如果你将 min-replicas-max-lag 设置为10，那么当从服务器的复制延迟超过10秒时，Sentinel不再将其视为可用的副本。
# 这是为了确保只有具有较低延迟的从服务器被认为是可用的，以防止可能导致数据不一致的情况。
# 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 and address 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 be actually 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.
# 设置从节点（replica）向主节点（master）报告其 IP 地址时使用的 IP 地址。
# replica-announce-ip 5.5.5.5
# 设置从节点（replica）向主节点（master）报告其端口号（port）时使用的端口号
# 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
# 16 millions of slots, what clients may have certain subsets of keys. In turn
# this is used in order to send invalidation messages to clients. Please
# to understand more about the feature check this page:
#
# 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.
# 设置 Redis 的跟踪表（tracking table）中最大键数目。
# 跟踪表是 Redis 服务器用于跟踪键的修改操作的内部数据结构
# 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 an 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.
# +<command> Allow the execution of that command
# -<command> Disallow the execution of that command
# +@<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>|subcommand Allow a specific subcommand of an otherwise
# disabled command. Note that this form is not
# allowed as negative like -DEBUG|SEGFAULT, but
# only additive starting with "+".
# 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.
# allkeys Alias for ~*
# resetkeys Flush the list of allowed keys patterns.
# ><password> Add this passowrd 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.
#
# 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.
#
# 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.
# 设置访问控制列表日志（ACL log）的最大长度。
# ACL 日志是用来记录 Redis 访问控制列表相关事件和操作的日志。
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 exteranl
# 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.
# 指定 Redis 使用的 ACL（Access Control List，访问控制列表）文件的路径
# aclfile /etc/redis/users.acl
# IMPORTANT NOTE: starting with Redis 6 "requirepass" is just a compatiblity
# 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.
# 设置 Redis 的连接密码（connection password），也称为认证密码（authentication password）或主密码（master password）
# 设置这个密码后，客户登录时要输入这个密码
# requirepass foobared
# 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.
# 设置 Redis 服务器同时接受的最大客户端连接数
# 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').
# 最大分配内容大小
# 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, Redis will return an error on write
# operations, when there are no suitable keys for eviction.
#
# At the date of writing these commands are: set setnx setex append
# incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd
# sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby
# zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby
# getset mset msetnx exec sort
#
# The default is:
# 设置 Redis 在达到最大内存限制时的内存管理策略
# noeviction 表示不会删除数据，如果使用Redis当数据库使用，则必须配置这个选项
# 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. For default Redis will check five keys and pick the one that was
# used less 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.
# 设置 Redis 在执行内存淘汰策略时使用的采样数
# 注意设置过大会增加内存淘汰的准确性，但也会增加执行淘汰策略的时间开销
# maxmemory-samples 5
# 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.
# 设置 Redis 主节点（master）是否允许从节点（replica）在达到最大内存限制时继续接收数据
# 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 tollerate less already expired keys still present
# in the system. It's a tradeoff betweeen memory, CPU and latecy.
# 设置 Redis 主动过期（active expire）策略的执行精确度和消耗的 CPU 资源
# 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.
# 控制 Redis 是否在执行驱逐（eviction）操作时使用延迟释放（lazy free）机制
lazyfree-lazy-eviction no
# 控制 Redis 是否在过期键时使用延迟释放机制
lazyfree-lazy-expire no
# 控制 Redis 是否在删除整个数据库时使用延迟释放机制
lazyfree-lazy-server-del no
# 控制 Redis 从节点（replica）在处理复制命令时是否使用延迟刷新策略
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:
# 控制 Redis 是否在用户显式删除键时使用延迟释放机制
lazyfree-lazy-user-del 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 speedup 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:
# 设置 Redis 使用的 I/O 线程数（网络I/O）
# io-threads 4
#
# Setting io-threads to 1 will just use the main thread as usually.
# 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:
# 控制 Redis 的读取操作是否由 I/O 线程处理
# 当 "io-threads-do-reads" 设置为 "no" 时，Redis 的 I/O 线程不会处理读取操作（reads），而是将其交给主事件循环线程（main event loop thread）来处理
# 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. Aso 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 theads, otherwise you'll not
# be able to notice the improvements.
############################## 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 http://redis.io/topics/persistence for more information.
# 是否开启AOF
appendonly no
# The name of the append only file (default: "appendonly.aof")
# Redis AOF持久化文件名
appendfilename "appendonly.aof"
# 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".
# Redis AOF 持久化级别（写入磁盘的速度），可配置为 alway=始终，everysec=每秒，no=根据系统缓冲区大小(4k)满flush决定。
# 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 none". 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.
# 当在执行RDB持久化时，是否继续执行AOF持久化，默认是不执行
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.
# AOF 持久化自动重写触发条件配置，重写会对AOF文件进行压缩，如果开启混合模式会加入RDB方案。
# 后续每次触发重写的条件是前一次触发重写后，再超过100%时触发重写
auto-aof-rewrite-percentage 100
# 开机后当aof文件达到64MB时会触发重写
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.
# 是否在启动时加载截断的 AOF 文件
# 即当 AOF 文件在写入过程中意外截断或损坏时，Redis 仍然会尽可能多地恢复数据。
# 启用该选项可以在某些情况下提供更好的数据恢复能力。但是截断的 AOF 文件可能包含不完整或损坏的数据，因此在加载时可能会导致数据不一致或错误。
aof-load-truncated yes
# When rewriting the AOF file, Redis is able to use an RDB preamble in the
# AOF file for faster rewrites and recoveries. When this option is turned
# on the rewritten AOF file is composed of two different stanzas:
#
# [RDB file][AOF tail]
#
# When loading Redis recognizes that the AOF file starts with the "REDIS"
# string and loads the prefixed RDB file, and continues loading the AOF
# tail.
# 是否开启AOF和RDB混合模式
aof-use-rdb-preamble yes
################################ LUA SCRIPTING ###############################
# Max execution time of a Lua script in milliseconds.
#
# If the maximum execution time is reached Redis will log that a script is
# still in execution after the maximum allowed time and will start to
# reply to queries with an error.
#
# When a long running script exceeds the maximum execution time only the
# SCRIPT KILL and SHUTDOWN NOSAVE commands are available. The first can be
# used to stop a script that did not yet called write commands. The second
# is the only way to shut down the server in the case a write command was
# already issued by the script but the user doesn't want to wait for the natural
# termination of the script.
#
# Set it to 0 or a negative value for unlimited execution without warnings.
# 执行 Lua 脚本的时间限制，Redis 将限制 Lua 脚本的执行时间在指定的毫秒数内
lua-time-limit 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:
# 是否启用 Redis 集群模式
# 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.
# 设置集群配置文件。这个文件不需要手动创建，Redis集群模式启动时会自动创建。
# 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 multiple of the node timeout.
# 设置 Redis 集群中节点之间的超时时间（毫秒）
# 如果一个节点在超过设定的超时时间内没有收到来自其他节点的心跳或消息，则该节点被认为是不可达的，并可能触发集群中的故障转移和重新分片操作
# cluster-node-timeout 15000
# 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 * replica-validity-factor) + repl-ping-replica-period
#
# So for example if node-timeout is 30 seconds, and the 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 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 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.
# 设置 Redis 集群中从节点的有效性因子（validity factor）。
# 有效性因子的计算基于从节点与主节点的连接状态和数据同步情况。当从节点与主节点失去连接或数据同步落后时，其有效性因子会逐渐下降。如果有效性因子降低到一个阈值以下（通常是 0），该从节点将被集群移除。
# 适当设置有效性因子可以在网络故障或节点失效时，从节点的可用性和数据一致性之间进行平衡。较高的有效性因子可以提高从节点的可用性，但可能导致数据一致性的延迟。较低的有效性因子可以更快地检测并移除故障的从节点，但可能降低可用性。
# 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.
# A value of 0 can be set but is useful only for debugging and dangerous
# in production.
# 设置 Redis 集群中的迁移屏障（migration barrier）。
# 在 Redis 集群中，当进行数据迁移或重新分片操作时，迁移屏障用于限制同时进行的迁移数量。迁移屏障的目的是避免大量的迁移操作同时进行，导致集群的网络和资源负载过高。
# cluster-migration-barrier 1
# By default Redis Cluster nodes stop accepting queries if they detect there
# is at least an 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.
# 设置 Redis 集群中是否要求完全覆盖（full coverage）哈希槽。哈希槽是 Redis 集群用于数据分片和负载均衡的基本单元。
# 在 Redis 集群中，完全覆盖是指所有哈希槽（hash slot）都被分配到集群中的节点，并且没有未分配的槽。
# cluster-require-full-coverage yes
# This option, when set to yes, prevents replicas from trying to failover its
# master during master failures. However the master 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.
# 是否允许从节点（replica）参与故障转移。
# 在 Redis 集群中，故障转移是指当主节点（master）发生故障或不可达时，将自动选择一个从节点作为新的主节点，以保持集群的可用性和数据一致性。
# cluster-replica-no-failover no
# This option, when set to yes, allows nodes to serve read traffic while the
# 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.
# 当主节点不可用时，是否允许在集群中的从节点进行读取操作。
# cluster-allow-reads-when-down no
# In order to setup your cluster make sure to read the documentation
# available at http://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 two options are used for this scope, and are:
#
# * cluster-announce-ip
# * cluster-announce-port
# * cluster-announce-bus-port
#
# Each instruct the node about its address, client port, 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 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 usually.
#
# Example:
# 集群节点在广播自身信息时使用的 IP 地址
# cluster-announce-ip 10.1.1.5
# 集群节点在广播自身信息时使用的 端口
# cluster-announce-port 6379
# 集群节点在广播自身信息时使用的 总线端口
# 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.
# 设置慢查询日志的阈值，即执行时间超过指定微秒数的命令将被记录到慢查询日志中。
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.
# 设置慢查询日志的最大长度，即慢查询日志中最多保存的条目数。
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.
# 设置延迟监控的阈值。
# 在 Redis 中，延迟监控用于记录执行时间超过指定阈值的命令的延迟情况。通过监控延迟，可以识别执行时间较长的命令，以及系统中的潜在性能问题。
latency-monitor-threshold 0
############################# EVENT NOTIFICATION ##############################
# Redis can notify Pub/Sub clients about events happening in the key space.
# This feature is documented at http://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)
# t Stream commands
# m Key-miss events (Note: It is not included in the 'A' class)
# A Alias for g$lshzxet, so that the "AKE" string means all the events
# (Except key-miss events which are excluded from 'A' due to their
# unique nature).
#
# The "notify-keyspace-events" takes as argument a string that is composed
# of zero or multiple characters. The empty string means that notifications
# are disabled.
#
# Example: to enable list and generic events, from the point of view of the
# event name, use:
#
# notify-keyspace-events Elg
#
# Example 2: to get the stream of the expired keys subscribing to channel
# name __keyevent@0__:expired use:
#
# notify-keyspace-events Ex
#
# By default all notifications are disabled because most users don't need
# this feature and the feature has some overhead. Note that if you don't
# specify at least one of K or E, no events will be delivered.
# 启用或禁用不同类型的键空间事件通知。
# 设置为空字符串 ""，表示禁用所有键空间事件通知。这意味着 Redis 将不会发送任何键空间事件通知。
# "K"：键空间通知，当有任何键被删除时触发通知。
# "E"：键空间通知，当有任何键被修改时触发通知。
# "g"：通用命令通知，当有任何通用命令（如 DEL、EXPIRE 等）被执行时触发通知。
# "s"：字符串命令通知，当有任何字符串命令（如 SET、GET 等）被执行时触发通知。
# "x"：过期事件通知，当有任何键过期时触发通知。
# "e"：驱逐事件通知，当有任何键被驱逐（evicted）时触发通知。
# "A"：参数事件通知，当添加或修改了 Redis 配置参数时触发通知。
# "l"：列表命令通知，当有任何列表命令（如 LPUSH、LRANGE 等）被执行时触发通知。
# "h"：哈希命令通知，当有任何哈希命令（如 HSET、HGETALL 等）被执行时触发通知。
# "z"：有序集合命令通知，当有任何有序集合命令（如 ZADD、ZRANK 等）被执行时触发通知。
# "x"：过期事件通知，当有任何键过期时触发通知。
# "$"：过期事件通知（每个键），当有任何键自然过期时触发通知。
notify-keyspace-events ""
############################### GOPHER SERVER #################################
# Redis contains an implementation of the Gopher protocol, as specified in
# the RFC 1436 (https://www.ietf.org/rfc/rfc1436.txt).
#
# The Gopher protocol was very popular in the late '90s. It is an alternative
# to the web, and the implementation both server and client side is so simple
# that the Redis server has just 100 lines of code in order to implement this
# support.
#
# What do you do with Gopher nowadays? Well Gopher never *really* died, and
# lately there is a movement in order for the Gopher more hierarchical content
# composed of just plain text documents to be resurrected. Some want a simpler
# internet, others believe that the mainstream internet became too much
# controlled, and it's cool to create an alternative space for people that
# want a bit of fresh air.
#
# Anyway for the 10nth birthday of the Redis, we gave it the Gopher protocol
# as a gift.
#
# --- HOW IT WORKS? ---
#
# The Redis Gopher support uses the inline protocol of Redis, and specifically
# two kind of inline requests that were anyway illegal: an empty request
# or any request that starts with "/" (there are no Redis commands starting
# with such a slash). Normal RESP2/RESP3 requests are completely out of the
# path of the Gopher protocol implementation and are served as usually as well.
#
# If you open a connection to Redis when Gopher is enabled and send it
# a string like "/foo", if there is a key named "/foo" it is served via the
# Gopher protocol.
#
# In order to create a real Gopher "hole" (the name of a Gopher site in Gopher
# talking), you likely need a script like the following:
#
# https://github.com/antirez/gopher2redis
#
# --- SECURITY WARNING ---
#
# If you plan to put Redis on the internet in a publicly accessible address
# to server Gopher pages MAKE SURE TO SET A PASSWORD to the instance.
# Once a password is set:
#
# 1. The Gopher server (when enabled, not by default) will still serve
# content via Gopher.
# 2. However other commands cannot be called before the client will
# authenticate.
#
# So use the 'requirepass' option to protect your instance.
#
# To enable Gopher support uncomment the following line and set
# the option from no (the default) to yes.
#
# gopher-enabled no
############################### 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.
# 哈希对象在使用 ziplist 编码时的最大条目数。
# 当哈希对象的条目数超过此阈值时，Redis 将自动转换为使用 hashtable 编码。
hash-max-ziplist-entries 512
# 哈希对象在使用 ziplist 编码时的最大值大小
hash-max-ziplist-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.
# 哈希对象在使用 ziplist 编码时的最大大小
list-max-ziplist-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.
# 列表数据结构在进行压缩时的深度
# 设置的深度为 0，表示禁用列表的压缩。
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.
# 设置集合数据结构在使用 intset 编码时的最大条目数
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:
# 用于设置有序集合在使用 ziplist 编码时的最大条目数
zset-max-ziplist-entries 128
# 用于设置有序集合在使用 ziplist 编码时的最大值大小
zset-max-ziplist-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.
# 使用稀疏存储方式时的最大字节数
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 entires limit by setting max-bytes to 0 and max-entries to the desired
# value.
# 设置流节点的最大字节数
stream-node-max-bytes 4096
# 设置流节点的最大条目数
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.
# 是否启用主动重新哈希（active rehashing）功能
# 设置yes，当哈希表的负载因子（load factor）超过一定阈值时，Redis 会自动触发重新哈希操作，即重新分布键值对到更大的哈希表中，以减少哈希冲突并保持查询性能。
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.
#
# Both the hard or the soft limit can be disabled by setting them to zero.
# 输出缓冲区的硬限制，当达到该限制时，Redis 将停止向客户端发送数据。
# 输出缓冲区的软限制，当达到该限制时，Redis 将暂停向客户端发送数据，直到缓冲区的大小降低到软限制以下。
# 暂停时间指达到软限制后，Redis 将暂停发送数据的时间长度（以秒为单位），超过该时间后，Redis 将继续向客户端发送数据。
# 限制普通客户端（normal）的输出缓冲区大小
# 这里表示输出缓冲区的硬限制、软限制和暂停时间均为 0，表示没有限制。
client-output-buffer-limit normal 0 0 0
# 限制复制节点客户端（replica）的输出缓冲区大小
# 这里表示输出缓冲区的硬限制为 256MB，软限制为 64MB，暂停时间为 60 秒。
# 当输出缓冲区超过软限制时，Redis 将暂停向复制节点客户端发送数据。
client-output-buffer-limit replica 256mb 64mb 60
# 限制发布订阅客户端（pubsub）的输出缓冲区大小
# 这里表示输出缓冲区的硬限制为 32MB，软限制为 8MB，暂停时间为 60 秒。
# 当输出缓冲区超过软限制时，Redis 将暂停向发布订阅客户端发送数据。
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.
# 设置客户端查询缓冲区的大小限制
# 客户端查询缓冲区用于存储待执行的命令请求。当客户端发送的命令请求超过缓冲区大小限制时，Redis 将停止接收额外的命令请求，直到已处理部分的查询被处理完毕。
# client-query-buffer-limit 1gb
# In the Redis protocol, bulk requests, that are, elements representing single
# strings, are normally limited ot 512 mb. However you can change this limit
# here.
# 设置 Redis 协议中的最大批量数据长度
# 批量数据指的是以特定格式传输的二进制安全字符串。通常，批量数据用于传输较大的值或数据块，如存储在 Redis 中的大型字符串或二进制文件。
# 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.
# 设置服务器的主循环执行频率（主循环周期），即每秒钟执行的循环次数。
# 服务器通过主循环来处理各种任务，包括接收客户端请求、执行命令、持久化数据、复制数据等。主循环的执行频率决定了服务器对这些任务的处理速度。
# 在给定的示例中，设置的频率为 10 次/秒。
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 temporary 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.
# 是否启用动态主循环执行频率（dynamic hz）功能
dynamic-hz yes
# When a child rewrites the AOF file, if the following option is enabled
# the file will be fsync-ed every 32 MB of data generated. This is useful
# in order to commit the file to the disk more incrementally and avoid
# big latency spikes.
# 是否启用增量方式的 AOF 文件同步
# 增量方式的文件同步会将数据缓存在内存中，并定期将缓存的数据同步到磁盘，而不是在每次写操作后都立即进行磁盘同步。这种方式可以提高 AOF 重写的性能和效率。
# 通过启用增量方式的 AOF 文件同步，Redis 在 AOF 重写过程中可以减少磁盘同步的次数，从而提高性能并降低磁盘 I/O 的负载。然而，需要注意的是，增量方式的文件同步可能会增加一定的数据丢失的风险，因为在数据缓存在内存中但尚未同步到磁盘时，系统发生故障可能会导致部分数据丢失。
aof-rewrite-incremental-fsync yes
# When redis saves RDB file, if the following option is enabled
# the file will be fsync-ed every 32 MB of data generated. This is useful
# in order to commit the file to the disk more incrementally and avoid
# big latency spikes.
# 是否启用增量方式的 RDB 文件同步。
# 增量方式的文件同步会将数据缓存在内存中，并定期将缓存的数据同步到磁盘，而不是在每次写操作后都立即进行磁盘同步。这种方式可以提高 RDB 持久化的性能和效率。
# 通过启用增量方式的 RDB 文件同步，Redis 在 RDB 持久化过程中可以减少磁盘同步的次数，从而提高性能并降低磁盘 I/O 的负载。然而，需要注意的是，增量方式的文件同步可能会增加一定的数据丢失的风险，因为在数据缓存在内存中但尚未同步到磁盘时，系统发生故障可能会导致部分数据丢失。
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 是一种用于缓存淘汰策略的算法之一。LFU 算法根据每个键的访问频率来确定其在缓存中的优先级。访问频率越高的键具有更高的优先级，从而更有可能被保留在缓存中。
# 设置 Least Frequently Used (LFU) 算法的日志因子
# 日志因子用于控制 LFU 算法中访问频率的增长速度。较高的日志因子会导致访问频率增长得更快，从而使得访问频率较高的键更长时间地保留在缓存中。
# 设置的日志因子为 10。这意味着每次访问一个键时，对应键的访问频率会增加 10 倍。较高的日志因子可以使得 LFU 算法更敏感地响应访问频率的变化，从而更好地适应访问模式的变化。
# 较高的日志因子可以提高命中率，但可能会增加内存消耗。较低的日志因子可能会导致更频繁的缓存淘汰，但可以减少内存消耗
# lfu-log-factor 10
# 设置 Least Frequently Used (LFU) 算法的衰减时间（秒）。，即用于衰减访问频率的时间窗口。衰减时间表示在多长时间内，对键的访问频率进行衰减。
# 衰减时间为 1。这意味着在每秒钟内，键的访问频率会衰减一次。较短的衰减时间可以使 LFU 算法更快地响应访问频率的变化，从而更好地适应访问模式的变化。
# 较短的衰减时间可以更快地适应访问模式的变化，但可能会导致频繁的键重新排序。较长的衰减时间可以稳定访问模式，但可能会导致缓存不及时地适应新的访问模式。
# 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 an "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.
# Enabled active defragmentation
# 是否启用主动碎片整理（active defragmentation）功能
# 主动碎片整理是 Redis 提供的一种机制，用于减少内存碎片并提高内存使用效率。当 Redis 存储的键值对被频繁地修改、删除或过期时，可能会导致内存碎片的产生。内存碎片会降低 Redis 的性能并占用额外的内存空间。
# 主动碎片整理会重新分配和重新排列内存中的键值对，使得存储在一起的键值对更紧密地排列在一起，从而减少内存碎片的发生。
# 禁用主动碎片整理可以减少对 CPU 和内存的额外开销，但可能会导致内存碎片的积累，从而影响 Redis 的性能和内存使用效率。
# activedefrag no
# Minimum amount of fragmentation waste to start active defrag
# 设置主动碎片整理（active defragmentation）功能中忽略的字节数阈值。
# 当某个 Redis 分片的内存碎片大小低于该阈值时，主动碎片整理功能将忽略对该分片的整理操作，以避免不必要的开销。
# 设置的阈值为 100MB，表示当某个 Redis 分片的内存碎片大小低于 100MB 时，主动碎片整理功能将忽略对该分片的整理操作。这意味着 Redis 只会对内存碎片较大的分片进行整理，以避免对小碎片进行不必要的操作。
# 较高的阈值可以减少主动碎片整理的频率，但可能会导致内存碎片的积累。较低的阈值会更频繁地触发主动碎片整理，但可能会增加一些额外的 CPU 和内存开销。
# 支持的单位包括 "b"（字节）、"kb"（千字节）、"mb"（兆字节）和 "gb"（千兆字节）
# active-defrag-ignore-bytes 100mb
# Minimum percentage of fragmentation to start active defrag
# 设置主动碎片整理（active defragmentation）功能中的下阈值。
# 下阈值表示当某个 Redis 分片的碎片率（fragmentation ratio）超过该阈值时，主动碎片整理功能将触发对该分片的整理操作。
# 设置的下阈值为 10，表示当某个 Redis 分片的碎片率超过 10% 时，主动碎片整理功能将触发对该分片的整理操作。碎片率是指被分配但未被使用的内存与总分配内存之间的比率。较高的下阈值将导致更频繁的整理操作，以减少内存碎片，但可能会增加一些额外的 CPU 和内存开销。
# 较低的下阈值可以更积极地减少内存碎片，但可能会增加主动碎片整理的开销。较高的下阈值会减少主动碎片整理的触发频率，但可能会导致内存碎片的积累。
# 这个值应该是一个介于 0 到 100 之间的整数，表示碎片率的百分比。
# active-defrag-threshold-lower 10
# Maximum percentage of fragmentation at which we use maximum effort
# 设置主动碎片整理（active defragmentation）功能中的上阈值。
# 上阈值表示当某个 Redis 分片的碎片率（fragmentation ratio）达到或超过该阈值时，主动碎片整理功能将强制对该分片进行整理操作。
# 设置的上阈值为 100，表示当某个 Redis 分片的碎片率达到或超过 100% 时，主动碎片整理功能将强制对该分片进行整理操作。碎片率是指被分配但未被使用的内存与总分配内存之间的比率。将上阈值设置为 100 表示始终触发整理操作，以减少任何程度的内存碎片。
# 较低的上阈值可以减少不必要的整理操作，但可能会导致内存碎片的积累。较高的上阈值会更积极地触发整理操作，以减少任何程度的内存碎片，但可能会增加一些额外的 CPU 和内存开销。
# 这个值应该是一个介于 0 到 100 之间的整数，表示碎片率的百分比。
# active-defrag-threshold-upper 100
# Minimal effort for defrag in CPU percentage, to be used when the lower
# threshold is reached
# 设置主动碎片整理（active defragmentation）功能的最小周期，即两次整理操作之间的最小时间间隔。单位为秒。
# 设置的最小周期为 1 秒，表示主动碎片整理功能在执行一次整理操作后，至少需要等待 1 秒才能再次执行下一次整理操作。
# 较小的周期可以更积极地进行整理操作，但可能会增加一些额外的 CPU 和内存开销。较大的周期可以减少整理操作的频率，降低开销，但也可能导致内存碎片的积累。
# active-defrag-cycle-min 1
# Maximal effort for defrag in CPU percentage, to be used when the upper
# threshold is reached
# 设置主动碎片整理（active defragmentation）功能的最大周期，次整理操作之间的最大时间间隔。单位为秒。
# 设置的最大周期为 25 秒，表示主动碎片整理功能在执行一次整理操作后，最多等待 25 秒才能执行下一次整理操作。如果在该时间间隔内没有发生其他触发整理操作的事件，则会在到达最大周期后执行下一次整理操作。
# 较小的周期可以更积极地进行整理操作，但可能会增加一些额外的 CPU 和内存开销。较大的周期可以减少整理操作的频率，降低开销，但也可能导致内存碎片的积累。
# active-defrag-cycle-max 25
# Maximum number of set/hash/zset/list fields that will be processed from
# the main dictionary scan
# 设置主动碎片整理（active defragmentation）功能中每次扫描的最大字段数。
# 当进行碎片整理操作时，Redis 会选择一些键值对进行整理，这个选项就限制了每次选择的键值对中最多包含的字段数。
# 设置的每次扫描的最大字段数为 1000。这意味着在进行主动碎片整理时，每次选择的键值对中最多将包含 1000 个字段。
# 较小的值会限制每次整理操作涉及的字段数，可能会减少整理操作的开销，但也可能导致整理效果不够充分。较大的值可以更全面地整理键值对，但可能会增加整理操作的开销。
# active-defrag-max-scan-fields 1000
# Jemalloc background thread for purging will be enabled by default
# 是否启用后台线程（background thread）来执行内存释放操作。
# 设置为 "yes" 时，jemalloc 将使用后台线程来异步执行内存释放操作，从而减少对主线程的阻塞时间。这可以提高应用程序的响应性能，尤其是在面对大量的内存释放操作时。
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:
# 设置服务器进程可使用的 CPU 核心列表。
# 设置的 CPU 列表为 "0-7:2"，表示服务器进程可以使用编号为 0、2、4、6 的 CPU 核心。
# 这是通过使用 CPU 核心的范围和步长来指定的。范围 "0-7" 表示从编号 0 的 CPU 核心到编号 7 的 CPU 核心，步长为 2 表示每隔一个 CPU 核心选择一个。
# 通过配置服务器进程可使用的 CPU 核心列表，可以对 Redis 在多核系统上的 CPU 分配进行控制。这可以用于优化性能，避免过多的线程竞争和资源浪费。
# 具体的 CPU 编号和可用的 CPU 核心数量取决于系统的硬件配置和操作系统的支持。您可以根据系统的实际情况调整 CPU 列表的设置。可以使用操作系统提供的工具来查看可用的 CPU 核心和它们的编号。
# server_cpulist 0-7:2
#
# Set bio threads to cpu affinity 1,3:
# 设置后台 I/O （Background I/O）线程可以使用的 CPU 核心列表。
# 设置的 CPU 列表为 "1,3"，表示后台 I/O 线程可以使用编号为 1 和 3 的 CPU 核心。
# 后台 I/O 线程负责处理与持久化操作相关的 I/O 操作，如保存到磁盘的写入操作。通过将后台 I/O 线程绑定到特定的 CPU 核心，可以优化系统的性能和资源利用率。
# 具体的 CPU 编号和可用的 CPU 核心数量取决于系统的硬件配置和操作系统的支持。您可以使用操作系统提供的工具来查看可用的 CPU 核心和它们的编号。
# bio_cpulist 1,3
#
# Set aof rewrite child process to cpu affinity 8,9,10,11:
# 设置 AOF 重写过程中的 CPU 核心列表。
# 设置的 CPU 列表为 "8-11"，表示 AOF 重写过程可以使用编号为 8 到 11 的 CPU 核心。
# aof_rewrite_cpulist 8-11
#
# Set bgsave child process to cpu affinity 1,10,11
# 设置后台保存过程中的 CPU 核心列表。
# 设置的 CPU 列表为 "1,10-11"，表示后台保存过程可以使用编号为 1、10 和 11 的 CPU 核心。
# 后台保存是 Redis 中的一项重要操作，用于将当前内存中的数据保存到磁盘上的快照文件中。这个过程可以用于持久化数据，以防止在 Redis 重启或崩溃时数据丢失。
# bgsave_cpulist 1,10-11
