手撕Redis6.0
原创大约 75 分钟
手撕Redis6.0,解刨他的内部。
简介
Redis 是完全开源免费的，遵守BSD协议，是一个高性能的key-value数据库。性能极高： Redis能读的速度是110000次/s,写的速度是81000次/s 。
安装
Linux下安装Redis。去年好像写过一次。。。传送门
下载
本次下载的是Redis官网最新稳定版本
# wget http://download.redis.io/releases/redis-6.0.3.tar.gz
解压
# tar -zxvf redis-6.0.3.tar.gz
注意：解压完成，尽量检查一下Redis所依赖的gcc版本，版本过低会编译失败。需要gcc 4.9以上。
升级gcc版本：
// 检查gcc版本
# gcc -v
// 升级gcc到9
# yum -y install centos-release-scl
# yum -y install devtoolset-9-gcc devtoolset-9-gcc-c++ devtoolset-9-binutils
# scl enable devtoolset-9 bash
// 以上为临时使用，如果长期使用执行下方：
# echo "source /opt/rh/devtoolset-9/enable" >>/etc/profile
编译
进入redis-6.0.3文件夹，进行编译。
# make PREFIX=/usr/local/redis install
安装成功会出现：
Hint: It's a good idea to run 'make test'
然后执行make test测试一下。最终出现：
All tests passed without errors!
注：如果出现tcl之类的错误，解决办法：
# yum install tcl
启动和关闭
直接启动： 注意自己的.conf文件和/bin/的路径
# ./bin/redis-server ./redis-6.0.3/redis.conf
后台启动： 编辑redis.conf，将daemonize on修改为 daemonize yes
# vi redis.conf
直接输入/daemonize 快速搜索，n是寻找下一个。找到位置之后，输入a开启编辑，然后Esc,输入:wq保存退出。再次使用上面的启动命令即可。
查看是否启动成功
# ps -ef | grep redis
简单使用
# ./bin/redis-cli
关闭方式一
# ./bin/redis-cli shutdown
关闭方式二 先查找出Redis的端口号，然后直接kill掉
# ps -ef | grep redis
-9 代表强制
# kill -9 39491
配置用户名和密码
版本6.0之前
编辑redis.conf，将requirepass 注释打开，后面跟上自己想要设置的密码。重启Redis即可 客户端连接输入密码的两种方式： 方式一： 先进入客户端，然后输入密码。
[root@localhost redis]# ./bin/redis-cli
127.0.0.1:6379> auth admin
方式二： 直接进入并输入密码
# ./bin/redis-cli -a admin
版本6.0之后
提供了ACL,可以设置用户名和密码。 官方文档https://redis.io/topics/acl 如果只是设置密码，那么用户名就是“default” 创建一个适用于生产环境的用户：
假如我这个用户redis环境主要用于gmaya-shop项目 那么我规定，这个用户使用的时候，所有存放的key必须以gmaya-shop:开头，不然不允许访问。只允许此用户使用get，和set命令。
127.0.0.1:6379> acl setuser gmayashopredis on >gmayapassword +get +set ~gmaya-shop:*
- 用户名：
gmayashopredis - 密码：
gmayapassword - 可用命令：
get，set - 可操作的key：
gmaya-shop:作为前缀的key
此时设置两个key
127.0.0.1:6379> set aaa 111
OK
127.0.0.1:6379> set gmaya-shop:userid 1001
OK
切换gmayashopredis 用户
127.0.0.1:6379> auth gmayashopredis gmayapassword
测试
127.0.0.1:6379> get aaa
(error) NOPERM this user has no permissions to access one of the keys used as arguments
127.0.0.1:6379> get gmaya-shop:userid
"1001"
ACL常用命令
查看当前用户:
127.0.0.1:6379> acl getuser gmayashopredis
1) "flags"
2) 1) "on"
3) "passwords"
4) 1) "74a3fbd0037d8c4c44137eb226451df5e5458446a768df424da0fd2a9938f7ba"
5) "commands"
6) "-@all +set +get"
7) "keys"
8) 1) "gmaya-shop:*"
查看所有命令：
127.0.0.1:6379> acl cat
增加命令减少命令：
127.0.0.1:6379> acl setuser gmayashopredis -get
OK
127.0.0.1:6379> acl setuser gmayashopredis +hget
OK
127.0.0.1:6379> acl getuser gmayashopredis
1) "flags"
2) 1) "on"
3) "passwords"
4) 1) "74a3fbd0037d8c4c44137eb226451df5e5458446a768df424da0fd2a9938f7ba"
5) "commands"
6) "-@all +set +hget"
7) "keys"
8) 1) "gmaya-shop:*"
刷新key的范围：
127.0.0.1:6379> acl setuser gmayashopredis resetkeys ~gmaya:*
OK
127.0.0.1:6379> acl getuser gmayashopredis
1) "flags"
2) 1) "on"
3) "passwords"
4) 1) "74a3fbd0037d8c4c44137eb226451df5e5458446a768df424da0fd2a9938f7ba"
5) "commands"
6) "-@all +set +hget"
7) "keys"
8) 1) "gmaya:*"
直接添加key：
127.0.0.1:6379> acl setuser gmayashopredis ~shop:*
OK
127.0.0.1:6379> acl getuser gmayashopredis
1) "flags"
2) 1) "on"
3) "passwords"
4) 1) "74a3fbd0037d8c4c44137eb226451df5e5458446a768df424da0fd2a9938f7ba"
5) "commands"
6) "-@all +set +hget"
7) "keys"
8) 1) "gmaya:*"
2) "shop:*"
添加密码减少密码
添加密码123456，减少密码gmayapassword，一个用户允许多个密码同时存在
127.0.0.1:6379> acl setuser gmayashopredis >123456
OK
127.0.0.1:6379> acl setuser gmayashopredis <gmayapassword
多线程
这次6.0版本加入了多线程模块。只有两个配置参数： 默认都是注释掉的。也就是不开启多线程
# io-threads 4 # 开启线程数
# io-threads-do-reads no # 是否开启多线程
通过下面的官方配置里面的介绍分析：
Redis主要是单线程的，但是也有一些特定的线程操作，比如断开链接、缓慢的I/O访问和其他在侧线程上执行的操作。- 默认情况下，线程是
禁用的，我们建议只在拥有至少4个或更多内核的机器上启用线程，而保留至少一个备用内核。使用8个以上的线程不太可能有太大的帮助。我们还建议仅当您确实存在性能问题时才使用线程I/O，因为Redis实例能够使用相当大的CPU时间百分比，否则使用此特性是没有意义的。 - 例如，如果你有
4个内核，尝试使用2或3个I/O线程，如果你有8个内核，尝试使用6个线程。 - 通常多线程读取不会有太大帮助。
Redis6.0配置文件解读
自己把redis配置文件拷贝出来一份，一行一行翻译一下。如果有不对的，希望指出来，虚心学习。
redis.config文件： 版本号：6.0.3注意：你可能要花很长时间来阅读这个配置。
TODO:有几个重点的地方，我还没来得及深入研究，大致已经清楚，后期肯定会写的。最近辞职回老家河南找工作了。
# Redis configuration file example.
#
# Note that in order to read the configuration file, Redis must be
# started with the file path as first argument:
# GMaya总结: redis在启动的时候,指定固定的配置文件启动。
# ./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.
# 引入其它配置文件
# 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.
#
# 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.
# 默认情况下，如果没有指定“bind”配置指令，则Redis侦听
# 对于来自服务器上可用的所有网络接口的连接。
# 可以只监听一个或多个选定的接口
# “bind”配置指令，后面跟着一个或多个IP地址。
# Examples:
#
# 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).
# 如果运行Redis的计算机直接暴露于
# 绑定到所有接口是危险的，将会暴露
# 互联网上的每个人。默认情况下，我们取消注释
# 遵循绑定指令，这将迫使Redis只监听
# IPv4环回接口地址(这意味着Redis将能够
# 只接受来自与it运行在同一台计算机上的客户机的连接
# 正在运行)。
# IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
# JUST COMMENT THE FOLLOWING LINE.
# 如果您确定希望实例侦听所有接口，注释下面的行。
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.
# GMaya总结： 保护模式开启时，需配置`bind ip`或者设置访问密码。
# 保护模式是一种安全防护层，以避免这种情况的发生
# 在internet上打开的Redis实例被访问和利用。
# When protected mode is on and if:
# 当保护模式开启时，如果:
# 1) The server is not binding explicitly to a set of addresses using the
# "bind" directive.
# 服务器没有使用“bind”指令显式地绑定到一组地址。，也就是说bind没有指定远程ip
# 2) No password is configured.
# 没有配置密码。
# 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.
# 服务器只接受从IPv4和IPv6环回地址127.0.0.1和::1，来自Unix域套接字。
# 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.
# 默认情况下，受保护模式是启用的。您应该仅在以下情况下禁用它
# 您确定希望来自其他主机的客户端连接到Redis
# 即使没有配置任何身份验证，也没有一组特定的接口
# 使用“bind”指令显式列出。
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.
# 接受指定端口上的连接，默认为6379 (IANA #815344)。
# 如果端口0被指定，Redis将不会监听TCP套接字。
port 6379
# TCP listen() backlog.
# 此参数和`somaxconn`确定了`TCP`连接中已完成队列(完成三次握手之后)的长度。
# 取两者最小值。当高并发的时候，可以考虑增加`somaxconn`的值，然后增加`tcp-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.
# 在每秒请求数很高的环境中，您需要按顺序进行高backlog
# 以避免慢速客户端连接问题。注意Linux内核
# 是否会静默地将其截断为/proc/sys/net/core/somaxconn的值
# 确保同时提高somaxconn和tcp_max_syn_backlog的值
# 以达到预期的效果。
tcp-backlog 511
# Unix socket.
#
# Specify the path for the Unix socket that will be used to listen for
# incoming connections. There is no default, so Redis will not listen
# on a unix socket when not specified.
#
# unixsocket /tmp/redis.sock
# unixsocketperm 700
# Close the connection after a client is idle for N seconds (0 to disable)
# 在客户端空闲N秒后关闭连接(0表示禁用)
timeout 0
# TCP keepalive.
# 表示将周期性的使用SO_KEEPALIVE检测客户端是否还处于健康状态，避免服务器一直阻塞。
# If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence
# of communication. This is useful for two reasons:
# 如果非零，使用SO_KEEPALIVE在客户端不存在时发送TCP ack
# 的沟通。这样做有两个原因:
# 1) Detect dead peers.
# 发现死去的客户端
# 2) Take the connection alive from the point of view of network
# equipment in the middle.
# 从网络设备的角度来看，连接在中间是活的
# 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.
# 在Linux上，指定的值(以秒为单位)是用于发送ack的周期。
# 注意，关闭连接需要双倍的时间。
# 在其他内核上，周期取决于内核配置。
# A reasonable value for this option is 300 seconds, which is the new
# Redis default starting with Redis 3.2.1.
# 这个选项的合理值是300秒，这是新的值
# Redis默认从Redis 3.2.1开始。
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:
#
# port 0
# tls-port 6379
# Configure a X.509 certificate and private key to use for authenticating the
# server to connected clients, masters or cluster peers. These files should be
# PEM formatted.
#
# tls-cert-file redis.crt
# tls-key-file redis.key
# Configure a DH parameters file to enable Diffie-Hellman (DH) key exchange:
#
# tls-dh-params-file redis.dh
# Configure a CA certificate(s) bundle or directory to authenticate TLS/SSL
# clients and peers. Redis requires an explicit configuration of at least one
# of these, and will not implicitly use the system wide configuration.
#
# tls-ca-cert-file ca.crt
# tls-ca-cert-dir /etc/ssl/certs
# By default, clients (including replica servers) on a TLS port are required
# to authenticate using valid client side certificates.
#
# It is possible to disable authentication using this directive.
#
# 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.
#
# tls-replication yes
# By default, the Redis Cluster bus uses a plain TCP connection. To enable
# TLS for the bus protocol, use the following directive:
#
# tls-cluster yes
# and include "TLSv1", "TLSv1.1", "TLSv1.2", "TLSv1.3" (OpenSSL >= 1.1.1)
#
# tls-protocols TLSv1.2
# Configure allowed ciphers. See the ciphers(1ssl) manpage for more information
# about the syntax of this string.
#
# Note: this configuration applies only to <= TLSv1.2.
#
# tls-ciphers DEFAULT:!MEDIUM
# Configure allowed TLSv1.3 ciphersuites. See the ciphers(1ssl) manpage for more
# information about the syntax of this string, and specifically for TLSv1.3
# ciphersuites.
#
# tls-ciphersuites TLS_CHACHA20_POLY1305_SHA256
# When choosing a cipher, use the server's preference instead of the client
# preference. By default, the server follows the client's preference.
#
# tls-prefer-server-ciphers yes
################################# 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.
# 默认情况下，Redis不作为守护进程运行。如果你需要，使用“yes”。
# 请注意，Redis将在/var/run/ Redis中写入一个pid文件。监控pid。
daemonize yes
# If you run Redis from upstart or systemd, Redis can interact with your
# supervision tree. Options:
# 如果你从upstart或systemd运行Redis, Redis可以与你的管理树交互。选项:
# supervised no - no supervision interaction 没有监督互动
# supervised upstart - signal upstart by putting Redis into SIGSTOP mode
# 通过将Redis置于SIGSTOP模式来启动信号
# supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET
# signal systemd将READY = 1写入$ NOTIFY_SOCKET
# supervised auto - detect upstart or systemd method based on
# UPSTART_JOB or NOTIFY_SOCKET environment variables
# 检测upstart或systemd方法基于 UPSTART_JOB或NOTIFY_SOCKET环境变量
# Note: these supervision methods only signal "process is ready."
# 注意:这些监督方法只表明“过程准备好了”。
# They do not enable continuous liveness pings back to your supervisor.
supervised no
# If a pid file is specified, Redis writes it where specified at startup
# and removes it at exit.
# 如果指定了pid文件，Redis会在启动时将其写入指定的位置
# 并在退出时删除它。
# 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".
# 当服务器运行非守护进程时，如果没有pid文件，则不创建pid文件
# 在配置中指定。当服务器以守护进程运行时，pid文件
# 即使未指定，默认也使用“/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.
# 创建一个pid文件是最好的努力，如果Redis不能创建它
# 没有什么不好的事情发生，服务器将正常启动和运行。（最好创建它，但是不创建也没事。）
pidfile /var/run/redis_6379.pid
# Specify the server verbosity level.
# 指定服务器详细日志级别。
# This can be one of:
# debug (a lot of information, useful for development/testing)
# 大量的信息，对开发/测试非常有用
# verbose (many rarely useful info, but not a mess like the debug level)
# 很多很少有用的信息，但不像调试级别那么混乱
# notice (moderately verbose, what you want in production probably)
# 有些冗长，这可能是您在生产环境中需要的
# warning (only very important / critical messages are logged)
# 只记录非常重要/关键的消息
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
# 指定日志文件名。此外，还可以使用空字符串强制Redis登录标准输出。
# 注意，如果使用标准输出进行日志记录，但是使用守护进程运行，那么日志将被发送到/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.
# 要启用系统日志记录器的日志功能，只需将'syslog-enabled'设置为yes，
# 并可选地更新其他syslog参数以满足您的需要。
# syslog-enabled no
# Specify the syslog identity.
# 指定syslog标识。
# syslog-ident redis
# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
# 指定syslog功能。必须是USER或介于LOCAL0-LOCAL7之间。
# 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
# 设置数据库的数量。默认数据库是DB 0，您可以选择
# 在每个连接的基础上使用SELECT <dbid>，其中
# dbid是一个介于0和‘databases’-1之间的数字。（也就是0到15）
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.
# 默认情况下，Redis只在开始登录时显示一个ASCII art徽标
# 标准输出，如果标准输出是TTY。基本上这意味着
# 标志通常只在交互式会话中显示。
# 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.
# 然而，强制执行4.0之前的行为并总是显示a是可能的
# 通过将以下选项设置为yes，可以在启动日志中显示ASCII art徽标。
always-show-logo yes
################################ SNAPSHOTTING ################################
# 持久化：RDB快照！！！！重点！
# Save the DB on disk:
# 将数据库保存在磁盘上:
# 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.
# 如果给定的秒数和给定的对该DB的写操作数同时发生，则将保存该DB。
# In the example below the behaviour will be to save:
# 在下面的例子中，行为将被保存:
# after 900 sec (15 min) if at least 1 key changed
# 在900秒(15分钟)后，如果至少改变了一个键
# after 300 sec (5 min) if at least 10 keys changed
# 300秒后(5分钟)如果至少10个键改变
# after 60 sec if at least 10000 keys changed
# 60秒后如果至少10000个键改变
# Note: you can disable saving completely by commenting out all "save" lines.
# 注意:您可以通过注释掉所有“保存”行来完全禁用保存。
# 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:
# 也可以删除以前配置的所有save
# 通过添加一个带有单个空字符串参数的save指令来获得
# 就像下面的例子:
# save ""
save 900 1
save 300 10
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.
# 默认情况下，如果启用了RDB快照,
# (至少一个保存点)和最新的后台保存失败,Redis将停止接受写操作.
# 这将使用户(以一种困难的方式)意识到数据不是持久的
# 正确地存储在磁盘上，否则没有人会注意到灾难将会发生。
# If the background saving process will start working again Redis will
# automatically allow writes again.
# 如果后台保存过程将再次开始工作，Redis将自动允许再次写入。
# 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.
# 但是，如果您已经设置了对Redis服务器的适当监视
# 和持久性，你可能想要禁用这个功能，这样Redis会
# 继续正常工作，即使有问题的磁盘，
# 权限等等。
# GMaya总结：如果存储数据（持久化）失败，则停止写入。
stop-writes-on-bgsave-error yes
# Compress string objects using LZF when dump .rdb databases?
# 在转储.rdb数据库时使用LZF压缩字符串对象?
# For default that's set to 'yes' as it's almost always a win.
# 默认情况下，它被设置为“yes”。
# 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.
# GMaya总结：是否开启对rdb持久化文件的压缩
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.
# 是否CRC64校验rdb文件，会有一定的性能损失（大概10%）。
# RDB files created with checksum disabled have a checksum of zero that will
# tell the loading code to skip the check.
# 禁用校验和创建的RDB文件的校验和为零
# 告诉加载代码跳过检查。
rdbchecksum yes
# The filename where to dump the DB
# rdb文件的名字。
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.
# 删除实例中复制使用的RDB文件，但不删除持久性
# 启用。默认情况下，这个选项是禁用的，但是有一些环境
# 对于法规或其他安全问题，RDB文件在哪里持久存在
# 主服务器通过磁盘来提供副本，或通过副本存储在磁盘上
# 为了加载它们进行初始同步，应该删除它们
# 尽快。注意，这个选项只在同时具有AOF的实例中起作用
# 并且禁用了RDB持久性，否则将完全忽略。
# 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.
# 另一种(有时是更好的)达到同样效果的方法是
#在主实例和副本实例上使用无磁盘复制。然而
#在副本的情况下，无磁盘并不总是一个选择。
rdb-del-sync-files no
# The working directory.
# 数据库存放目录。
# The DB will be written inside this directory, with the filename specified
# above using the 'dbfilename' configuration directive.
# DB将在此目录中写入，并指定文件名
# 上面使用'dbfilename'配置指令。
# The Append Only File will also be created inside this directory.
# 仅追加文件也将在此目录中创建（AOF文件也在这个目录创建）
# Note that you must specify a directory here, not a file name.
# 注意，这里必须指定一个目录，而不是文件名。
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.
# 主从复制
# +------------------+ +---------------+
# | 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.
# Redis复制是异步的，但是您可以配置一个主服务器来停止接受写操作，如果它看起来至少没有连接到给定数量的副本。
# 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.
# GMaya总结：5.0及之后版本replicaof代替了slaveof.
# 在这里配置属于永久配置，replicaof 主ip 主端口。只有从的需要配置，主的不需要
# 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.
# 如果主服务器是密码保护的(使用下面的“requirepass”配置指令)，可以在启动复制同步进程之前告诉副本进行身份验证，否则主服务器将拒绝副本请求。
# 也就是如果你的主设置了密码，这个地方需要写上主的密码，才能连接上
# 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:
# 但是，如果您使用的是Redis acl(适用于Redis版本6或更高版本)，并且默认用户不能运行PSYNC命令和/或复制所需的其他命令，那么这还不够。
# 在这种情况下，最好配置一个特殊用户与复制一起使用，并指定masteruser配置如下:
# 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:
# 当副本失去与主副本的连接时，或者复制仍在进行时，副本可以以两种不同的方式执行操作:
# 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.
# 如果replica-serve-stale-data被设置为“yes”(默认值)，则副本将执行此操作
# 仍然响应客户端请求，可能是数据过期，或者如果这是第一次同步，那么数据集可能是空的。
# 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.
# 如果replica-serve-stale-data被设置为“no”
# 除了INFO, replicaOF, AUTH, PING, SHUTDOWN, REPLCONF, ROLE, CONFIG，订阅，取消订阅，PSUBSCRIBE, PUNSUBSCRIBE，发布，PUBSUB，命令，发布，主机:和延迟。
# 其他的都会返回“与主进程同步”错误
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.
# 默认情况下Redis 2.6的副本是只读的。
# 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.
# 也就是从库只允许读，不允许写，读写分离啊
replica-read-only yes
# Replication SYNC strategy: disk or socket.
# 复制同步策略:磁盘或套接字。
# 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.
# 对于慢速磁盘和快速(大带宽)网络，无磁盘复制工作得更好。
# 主从数据复制是否使用无硬盘复制功能。
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.
# 当启用无磁盘复制时，可以配置服务器等待的延迟，以生成通过套接字传输RDB的子节点的副本。
#
# 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.
# diskless复制的延迟时间
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)
# 不要使用无磁盘加载(首先将rdb文件存储到磁盘)
# "on-empty-db" - Use diskless load only when it is completely safe.
# 只有在完全安全的情况下才使用无磁盘加载。
# "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.
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.
#
# 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.
# 复制连接超时时间。
# 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.
# 是否禁止复制tcp链接的tcp nodelay参数
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.
# 复制待办事项列表越大，副本断开连接的时间就越长，并且以后能够执行部分重新同步。
# The backlog is only allocated once there is at least a replica connected.
# 积压只在至少连接了一个副本时才分配。
# 复制缓冲区大小
# 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.
# 0的值意味着永远不释放积压。
# master没有slave一段时间会释放复制缓冲区的内存，repl-backlog-ttl用来设置该时间长度。单位为秒。
# 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.
# 副本优先级是一个由Redis在信息中发布的整数输出。Redis Sentinel使用它来选择一个副本，以便在主服务器不再正常工作时将副本提升到主服务器。
# 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.
# 低优先级的副本被认为更适合升级，例如，如果有3个优先级为10,100，25的副本，Sentinel将选择优先级为10的副本，这是最低的。
# 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.
# 但是一个特殊的优先级为0的副本将不能执行master的角色，所以一个优先级为0的副本将永远不会被Redis Sentinel选中进行升级。
#
# By default the priority is 100.
# 默认情况下，优先级是100。
# 也就是当主机挂了，从机那个优先级低，那个就会被推选为主机。
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.
# 如果连接的副本少于N个，延迟小于或等于M秒，那么主机可能会停止接受写操作。
# The N replicas need to be in "online" state.
# N个副本需要处于“在线”状态。
# 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.
# N个副本以秒为单位的延迟(必须<=指定的值)是从副本接收的最后一个ping，通常每秒发送一次。需要处于“在线”状态。
# 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.
# 此选项不保证N个副本将接受写操作，但在没有足够的副本可用的情况下，将把丢失的写操作的曝光窗口限制在指定的秒数内。
# For example to require at least 3 replicas with a lag <= 10 seconds use:
# 例如，需要至少3个 从机 延迟小于等于 10秒 才会写入
# min-replicas-to-write 3
# min-replicas-max-lag 10
#
# Setting one or the other to 0 disables the feature.
# 将其中一个设置为0将禁用该特性。
# By default min-replicas-to-write is set to 0 (feature disabled) and
# min-replicas-max-lag is set to 10.
# 默认情况下，最小复制写入设置为0(禁用特性)
# 最小复制最大延迟设置为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.
# Redis主服务器能够以不同的方式列出所附副本的地址和端口。例如，“信息复制”部分提供了这些信息，Redis Sentinel使用这些信息和其他工具来发现副本实例。
# 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.
#
# replica-announce-ip 5.5.5.5
# replica-announce-port 1234
############################### KEYS TRACKING #################################
# Redis implements server assisted support for client side caching of values.
# This is implemented using an invalidation table that remembers, using
# 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.
# 这个是有关客户端缓存的
# tracking-table-max-keys 1000000
################################## SECURITY ###################################
# 安全，在6.0版本之后，加入了用户名+密码的设置，如果设置密码，用户名为默认。
# 新格式：AUTH <username> <password> 或者 旧格式：AUTH <password>
# 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:
# 描述用户可以做什么的ACL规则如下所示
# on Enable the user: it is possible to authenticate as this user.启用用户:可以作为此用户进行身份验证。
# off Disable the user: it's no longer possible to authenticate
# with this user, however the already authenticated connections
# will still work.
# 禁用该用户:不再能够使用该用户进行身份验证，但是已验证的连接仍然可以工作。
# +<command> Allow the execution of that command 允许执行该命令，也就是添加用户命令权限，例：+get +set
# -<command> Disallow the execution of that command 不允许执行该命令
# +@<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.
# 添加可作为命令的一部分提到的键的模式。例如~*允许所有的键。模式是一个全局样式的模式，类似于键的模式。可以指定多个模式。
# GMaya总结：也就是允许访问那些key，例子：只允许访问~gmaya:*开头的key。如：gmaya:userid， gmaya:roleid
# allkeys Alias for ~* allkeys别名为~*
# resetkeys Flush the list of allowed keys patterns.刷新允许的键模式列表。
# ><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).
# 将这个passowrd添加到用户的有效密码列表中。例如，>mypass会将“mypass”添加到列表中。这个指令清除“nopass”标志(参见后面)。
# <<password> Remove this password from the list of valid passwords. 从有效密码列表中删除此密码。
# 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.
# 删除用户的所有设置密码，并将用户标记为不需要密码:这意味着每个密码都将对该用户起作用。如果此指令用于默认用户，
# 则每个新连接都将立即与默认用户进行身份验证，而不需要任何显式的AUTH命令。注意“resetpass”指令将清除这个条件。
# 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).\
# 刷新允许的密码列表。此外，删除“nopass”状态。在“resetpass”之后，用户没有相关联的密码，并且没有办法在不添加一些密码(或稍后将其设置为“nopass”)的情况下进行身份验证。
# reset Performs the following actions: resetpass, resetkeys, off,
# -@all. The user returns to the same state it has immediately
# after its creation.
# 执行以下操作:resetpass、resetkeys、off、-@all。用户在创建后立即返回到相同的状态。
# 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 and consumes memory. There is no limit
# to its length.You can reclaim memory with ACL LOG RESET or set a maximum
# length below.
acllog-max-len 128
# Using an external ACL file
# 使用外部ACL文件
# 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.
# 不需要在这个文件中配置用户，可以使用一个单独的文件来列出用户。这两种方法不能混合使用:如果在这里配置用户，同时激活exteranl ACL文件，服务器将拒绝启动。
# The format of the external ACL user file is exactly the same as the
# format that is used inside redis.conf to describe users.
# 外部ACL用户文件的格式与在redis.conf中用于描述用户的格式完全相同。
# 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.
# 密码，如果使用redis需要密码，在这里设置
# requirepass foobared
# Command renaming (DEPRECATED).
# 命令重命名(弃用)。
# ------------------------------------------------------------------------
# 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).
# 同时设置最大连接客户端数量。默认情况下这个限制设置为10000个客户,
# 但是如果复述,服务器不能配置过程文件限制允许指定限制允许的最大数量的客户设置为（当前文件限制- 32）(redis本身会用到32左右的连接,储备一些为内部使用文件描述符)。
# Once the limit is reached Redis will close all the new connections sending
# an error 'max number of clients reached'.
# 一旦达到限制，Redis将关闭所有新连接，发送一个错误“达到的客户端最大数量”。
# maxclients 10000
############################## MEMORY MANAGEMENT ################################
# 内存管理
# 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').
# 指定Redis最大内存限制
# maxmemory <bytes>
# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
# is reached. You can select one from the following behaviors:
# 当内存使用达到最大值时，redis使用的清除策略。
# volatile-lru -> Evict using approximated LRU, only keys with an expire set. 使用近似LRU，仅使用具有过期设置的键。
# allkeys-lru -> Evict any key using approximated LRU. 使用近似LRU退出任何key。
# volatile-lfu -> Evict using approximated LFU, only keys with an expire set. 使用近似的LFU，仅使用具有过期集的键。
# allkeys-lfu -> Evict any key using approximated LFU. 使用近似的LFU退出任何键。
# volatile-random -> Remove a random key having an expire set. 删除具有过期集的随机key
# allkeys-random -> Remove a random key, any key. 删除一个随机key，任何key。
# volatile-ttl -> Remove the key with the nearest expire time (minor TTL) 删除具有最近过期时间的密钥(次要TTL)
# noeviction -> Don't evict anything, just return an error on write operations. 不删除任何内容，只在写操作时返回一个错误。
#
# LRU means Least Recently Used # LRU的意思是最近最少使用的
# LFU means Least Frequently Used # LFU的意思是最不常用的
#
# Both LRU, LFU and volatile-ttl are implemented using approximated
# randomized algorithms.
# LRU、LFU和volatile-ttl都是使用近似随机算法实现的。
#
# 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:
#
# 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.
# LRU、LFU和最小TTL算法并不是精确的算法，而是近似的算法(为了节省内存)，因此您可以对其进行调优以获得速度或精度。
# 对于默认情况，Redis将检查五个键并选择最近较少使用的键，您可以使用以下配置指令更改样本大小。
#
# 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.
# 默认的5产生足够好的结果。10非常接近真实的LRU，但是消耗更多的CPU。3更快，但不是很准确。
# 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.
# 从Redis 5开始，在默认情况下，副本将忽略它的maxmemory设置(除非在故障转移后或手动将其提升为master)。
# 这意味着键的回收将只由主进程处理，当主进程中的键被回收时，将DEL命令发送到副本。
# 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.
# 注意，由于副本在默认情况下不会被逐出，因此它最终使用的内存可能比通过maxmemory设置的内存多(在副本上有一些缓冲区可能更大，或者数据结构有时会占用更多内存，等等)。
# 因此，请确保您监控您的副本，并确保他们有足够的内存，从来没有遇到真正的内存不足的情况之前master点击已配置的maxmemory设置。
# 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.
# Redis以两种方式回收过期的密钥:在访问时发现这些密钥已经过期，在后台，也称为“活动过期密钥”。
# 对密钥空间进行缓慢而交互式的扫描，寻找过期的密钥进行回收，以便释放过期的密钥的内存，这些密钥在短时间内永远不会被再次访问。
# 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.
# 过期周期的默认工作将尝试避免在内存中保留超过10%的过期密钥，并尝试避免消耗超过25%的总内存并增加系统延迟。但是，可以将过期的“工作”(通常设置为“1”)增加到更大的值，直到值“10”。
# 在其最大值时，系统将使用更多的CPU，更长的周期(技术上可能引入更多的延迟)，并且将减少系统中仍然存在的过期密钥。这是内存、CPU和延迟之间的权衡。
# active-expire-effort 1
############################# LAZY FREEING ####################################
# 延迟加载
# 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.
# Redis有两个原语来删除键。一个是DEL，是对象的阻塞删除。它意味着服务器停止处理新命令，以便以同步方式回收与对象关联的所有内存。
# 如果删除的键与一个小对象相关联，那么执行DEL命令所需的时间非常短，可以与Redis中的大多数其他O(1)或O(log_N)命令相媲美。
# 但是，如果键与包含数百万个元素的聚合值相关联，服务器可能会阻塞很长时间(甚至几秒钟)以完成操作。
# 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.
# 因为将数据存储在可能已经存在的键上的命令的副作用。例如，重命名命令可以删除替换为其他键内容的旧键内容。
# 类似地，SUNIONSTORE或使用STORE选项排序可以删除现有密钥。SET命令本身删除指定键的任何旧内容，以便用指定的字符串替换它。
# 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.
# 在复制期间，当一个副本执行与其主副本的完全重新同步时，将删除整个数据库的内容，以便加载刚刚传输的RDB文件。
#
# 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.
# 在上述所有情况下，默认情况是以阻塞的方式删除对象，就像调用DEL一样。
# 但是，您可以专门配置每种情况，以便以非阻塞的方式释放内存，就像调用UNLINK一样，使用以下配置指令。
lazyfree-lazy-eviction no
# 是否开启基于lazyfree的驱逐功能 yes，表示开启。no，默认值，表示不开启。
lazyfree-lazy-expire no
# 是否开启基于lazyfree的过期key删除功能，
lazyfree-lazy-server-del no
# RENAME、SUNIONSTORE等命令是否基于lazyfree异步删除数据
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
# 在用UNLINK调用替换DEL调用的用户代码不容易的情况下，也可以使用以下配置修改DEL命令的默认行为，使其行为与UNLINK完全一样
# directive:
# 执行DEL命令时是否基于lazyfree异步删除数据
lazyfree-lazy-user-del no
################################ THREADED I/O #################################
# 多线程
# 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.
# Redis主要是单线程的，但是也有一些特定的线程操作，比如断开链接、缓慢的I/O访问和其他在侧线程上执行的操作。
# 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.
# 默认情况下，线程是禁用的，我们建议只在拥有至少4个或更多内核的机器上启用线程，而保留至少一个备用内核。使用8个以上的线程不太可能有太大的帮助。
# 我们还建议仅当您确实存在性能问题时才使用线程I/O，因为Redis实例能够使用相当大的CPU时间百分比，否则使用此特性是没有意义的。
# 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:
# 例如，如果你有4个内核，尝试使用2或3个I/O线程，如果你有8个内核，尝试使用6个线程。为了启用I/O线程使用以下配置指令:
# 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:
# 将io线程设置为1只会像往常一样使用主线程。当启用I/O线程时，我们只使用线程进行写操作，
# 即线程写系统调用并将客户端缓冲区传输到套接字。然而，也可以启用线程读取和协议解析使用以下配置指令，通过设置为yes:
#
# io-threads-do-reads no
#
# Usually threading reads doesn't help much.
# 通常线程读取不会有太大帮助。哈哈，也就是百分之八十的人用不到这个玩意儿。
# NOTE 1: This configuration directive cannot be changed at runtime via
# CONFIG SET. Aso this feature currently does not work when SSL is
# enabled.
# 这个配置指令不能在运行时通过配置集进行更改。当启用SSL时，此功能当前无法工作。
# 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.
# 如果您想使用Redis -benchmark测试Redis加速，请确保您也在线程模式下运行基准测试本身，使用——threads选项来匹配Redis头的数量，否则您将无法注意到这些改进。
############################## APPEND ONLY MODE ###############################
# 追加模式
# 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).
# 默认情况下，Redis异步地将数据转储到磁盘上。这种模式在许多应用程序中已经足够好了，但是Redis进程或断电可能会导致几分钟的写丢失(取决于配置的保存点)。
# 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.
# Append Only文件是另一种持久性模式，它提供了更好的持久性。
# 例如使用默认数据fsync策略配置文件中(见后)复述,可以失去只是一秒的写在一个戏剧性的事件像一个服务器断电,或一个写如果复述过程本身出了问题,但正确操作系统仍在运行。
#
# 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.
# 可以同时启用AOF和RDB持久性，不会出现问题。如果启动时启用了AOF，则Redis将加载AOF，这是具有更好持久性保证的文件。
# Please check http://redis.io/topics/persistence for more information.
# 是否开启aof持久化。默认不开启
appendonly no
# The name of the append only file (default: "appendonly.aof")
# 仅追加文件的名称(默认:“appendonly.aof”)
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.
# fsync()调用告诉操作系统实际在磁盘上写入数据，而不是等待输出缓冲区中的更多数据。一些操作系统会真正地刷新磁盘上的数据，而另一些操作系统只是试图尽快完成。
# Redis supports three different modes:
# Redis支持三种不同的模式:
# no: don't fsync, just let the OS flush the data when it wants. Faster.
# 从不fsync，只需将数据交给操作系统即可。更快，更不安全的方法。通常，Linux使用此配置每30秒刷新一次数据，但这取决于内核的精确调整。
# always: fsync after every write to the append only log. Slow, Safest.
# fsync每次将新命令附加到AOF时。非常非常慢，非常安全。
# everysec: fsync only one time every second. Compromise.
# fsync每秒。速度足够快（在2.4中可能与快照速度一样快），如果发生灾难，您可能会丢失1秒的数据。
#
# 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.
# 默认值是“everysec”，因为这通常是速度和数据安全性之间的正确折衷。由你理解如果你能放松这个“不”字,让操作系统刷新输出缓冲区时,
# 为了更好的表现(但是如果你可以忍受一些数据丢失的想法考虑默认快照的持久性模式),或相反,使用“总是”非常缓慢但比everysec更安全一点。
# More details please check the following article:
# http://antirez.com/post/redis-persistence-demystified.html
#
# If unsure, use "everysec".
# 如果不确定，使用“everysec”。
# appendfsync always
appendfsync everysec
# appendfsync no
# When the AOF fsync policy is set to always or everysec, and a background
# saving process (a background save or AOF log background rewriting) is
# performing a lot of I/O against the disk, in some Linux configurations
# Redis may block too long on the fsync() call. Note that there is no fix for
# this currently, as even performing fsync in a different thread will block
# our synchronous write(2) call.
#
# In order to mitigate this problem it's possible to use the following option
# that will prevent fsync() from being called in the main process while a
# BGSAVE or BGREWRITEAOF is in progress.
#
# This means that while another child is saving, the durability of Redis is
# the same as "appendfsync 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.
# 如果你有延迟问题，将此选项变为“yes”。否则，从耐久性的角度来看，“no”是最安全的选择。
no-appendfsync-on-rewrite no
# Automatic rewrite of the append only file.
# 自动重写仅追加文件。
# Redis is able to automatically rewrite the log file implicitly calling
# BGREWRITEAOF when the AOF log size grows by the specified percentage.
# Redis能够在日志大小按指定百分比增长时自动重写隐式调用BGREWRITEAOF的日志文件。
# 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).
# 它是这样工作的:Redis记住了最近一次重写后的AOF文件的大小(如果重新启动后没有发生重写，则使用启动时的AOF大小)。
#
# 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.
# 这个基本大小与当前大小进行比较。如果当前大小大于指定的百分比，则会触发重写。
# 此外，您还需要为要重写的AOF文件指定最小的大小，这对于避免重写AOF文件非常有用，即使百分比会增加到达，但它仍然是相当小的。
# Specify a percentage of zero in order to disable the automatic AOF
# rewrite feature.
# 指定零的百分比，以禁用自动AOF重写特性。
# 当文件超过上次rewrite的百分之百的时候就会重写。
# 对于下面的我是这样认为的：
# 当前AOF文件大小超过上一次重写的AOF文件大小的百分之多少才会重写
# 即为：当文件超过64mb开启重写，如果超过64的百分之百，也就是超过64*2=128的时候再次重写。
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
# An AOF file may be found to be truncated at the end during the Redis
# startup process, when the AOF data gets loaded back into memory.
# This may happen when the system where Redis is running
# crashes, especially when an ext4 filesystem is mounted without the
# data=ordered option (however this can't happen when Redis itself
# crashes or aborts but the operating system still works correctly).
#
# Redis can either exit with an error when this happens, or load as much
# data as possible (the default now) and start if the AOF file is found
# to be truncated at the end. The following option controls this behavior.
#
# If aof-load-truncated is set to yes, a truncated AOF file is loaded and
# the Redis server starts emitting a log to inform the user of the event.
# Otherwise if the option is set to no, the server aborts with an error
# and refuses to start. When the option is set to no, the user requires
# to fix the AOF file using the "redis-check-aof" utility before to restart
# the server.
#
# Note that if the AOF file will be found to be corrupted in the middle
# the server will still exit with an error. This option only applies when
# Redis will try to read more data from the AOF file but not enough bytes
# will be found.
# 注意，如果AOF文件在中间被破坏，服务器仍然会带着错误退出。这个选项只适用于当Redis试图从AOF文件读取更多的数据，但没有足够的字节将被发现。
# redis在启动时可以加载被截断的AOF文件
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:
# 当重写AOF文件时，Redis能够在AOF文件中使用一个RDB序言，以便更快地重写和恢复。当这个选项打开时，重写的AOF文件由两个不同的节组成:
# [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.
# 当加载Redis时，它识别出AOF文件以“Redis”字符串开始并加载前缀RDB文件，然后继续加载AOF尾部。
aof-use-rdb-preamble yes
################################ LUA SCRIPTING ###############################
# LUA脚本
# Max execution time of a Lua script in milliseconds.
# Lua脚本的最大执行时间(以毫秒为单位)
# 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.
# 如果达到最大执行时间，Redis将记录脚本在最大允许时间之后仍在执行，并开始用错误回复查询。
# 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.
# 将其设置为0或负值，以便在没有警告的情况下无限执行。
lua-time-limit 5000
################################ REDIS CLUSTER ###############################
# 分布式集群配置
# 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:
# 正常的Redis实例不能成为Redis集群的一部分;只有作为集群节点启动的节点可以。为了启动一个Redis实例作为一个集群节点启用集群支持取消注释如下:
# 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.
# 每个集群节点都有一个集群配置文件。此文件不打算手工编辑。它由Redis节点创建和更新。
# 每个Redis集群节点都需要一个不同的集群配置文件。确保在同一系统中运行的实例没有重叠的集群配置文件名。
# 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.
# 群集节点超时是节点必须不可达的毫秒数，以便将其视为故障状态。
# Most other internal time limits are multiple of the node timeout.
# 大多数其他内部时间限制是多个节点超时。
# cluster-node-timeout 15000
# A replica of a failing master will avoid to start a failover if its data
# looks too old.
# 如果数据看起来太旧，失败主服务器的副本将避免启动故障转移。
# 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.
#
# 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.
#
# 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.
#
# 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.
#
# 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.
#
# 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:
#
# cluster-announce-ip 10.1.1.5
# cluster-announce-port 6379
# 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).
# Redis慢日志是一个记录超过指定执行时间的查询的系统。执行时间不包括I / O操作,比如与客户端,发送应答等等,
# 但就实际执行命令所需的时间(这是唯一阶段命令执行的线程被阻塞,不能同时处理其他请求)。
# 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.
# 您可以使用两个参数配置慢日志:一个参数告诉Redis命令的执行时间(以微秒为单位)超过了多少，
# 以便记录命令，另一个参数是慢日志的长度。当记录一个新命令时，将从记录的命令队列中删除最旧的命令。
# 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.
# 下面的时间用微秒表示，所以1000000等于1秒。注意，负数会禁用慢日志，而值0则强制对每个命令进行日志记录。
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.
# 这个长度没有限制。请注意，它会消耗内存。您可以通过重新设置慢日志来回收慢日志使用的内存。
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.
# Redis延迟监视子系统在运行时采样不同的操作，以便收集与Redis实例的潜在延迟源相关的数据。
# Via the LATENCY command this information is available to the user that can
# print graphs and obtain reports.
# 通过LATENCY命令，可以将此信息提供给能够打印图形和获取报告的用户。
# 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.
# 系统只记录在等于或大于通过延迟监视阈值配置指令指定的毫秒数的时间内执行的操作。当其值设置为零时，延迟监控器将被关闭。
# 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.
# 默认情况下，延迟监视是禁用的，因为如果没有延迟问题，那么基本上不需要延迟监视，而且收集数据对性能有影响，虽然非常小，但是可以在大负载下测量。
# 如果需要，可以在运行时使用“latency-monitor-threshold <milliseconds>”命令轻松启用延迟监视
# 延时监控的采样时间阈值（最小值）。单位毫秒
latency-monitor-threshold 0
############################# EVENT NOTIFICATION ##############################
# 事件通知
# 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.
# 键空间通知，配置该参数后客户端可以通过Redis的订阅与发布功能，来接收那些以某种方式改动了Redis数据集的事件。
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 ###############################
# 高级配置
# 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.
# 当有少量条目且最大条目不超过给定阈值时，使用内存有效数据结构对哈希进行编码。可以使用以下指令配置这些阈值。
hash-max-ziplist-entries 512
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.
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.
list-compress-depth 0
# Sets have a special encoding in just one case: when a set is composed
# of just strings that happen to be integers in radix 10 in the range
# of 64 bit signed integers.
# The following configuration setting sets the limit in the size of the
# set in order to use this special memory saving encoding.
set-max-intset-entries 512
# Similarly to hashes and lists, sorted sets are also specially encoded in
# order to save a lot of space. This encoding is only used when the length and
# elements of a sorted set are below the following limits:
zset-max-ziplist-entries 128
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.
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.
stream-node-max-bytes 4096
stream-node-max-entries 100
# Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in
# order to help rehashing the main Redis hash table (the one mapping top-level
# keys to values). The hash table implementation Redis uses (see dict.c)
# performs a lazy rehashing: the more operation you run into a hash table
# that is rehashing, the more rehashing "steps" are performed, so if the
# server is idle the rehashing is never complete and some more memory is used
# by the hash table.
#
# The default is to use this millisecond 10 times every second in order to
# actively rehash the main dictionaries, freeing memory when possible.
#
# If unsure:
# use "activerehashing no" if you have hard latency requirements and it is
# not a good thing in your environment that Redis can reply from time to time
# to queries with 2 milliseconds delay.
# 当你的使用场景中，有非常严格的实时性需要，不能够接受Redis时不时的对请求有2毫秒的延迟的话，把这项配置为no
# use "activerehashing yes" if you don't have such hard requirements but
# want to free memory asap when possible.
# 如果没有这么严格的实时性要求，可以设置为yes，以便能够尽可能快的释放内存
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.
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit replica 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
# Client query buffers accumulate new commands. They are limited to a fixed
# amount by default in order to avoid that a protocol desynchronization (for
# instance due to a bug in the client) will lead to unbound memory usage in
# the query buffer. However you can configure it here if you have very special
# needs, such us huge multi/exec requests or alike.
#
# client-query-buffer-limit 1gb
# In the Redis protocol, bulk requests, that are, elements representing single
# strings, are normally limited ot 512 mb. However you can change this limit
# here.
#
# proto-max-bulk-len 512mb
# Redis calls an internal function to perform many background tasks, like
# closing connections of clients in timeout, purging expired keys that are
# never requested, and so forth.
#
# Not all tasks are performed with the same frequency, but Redis checks for
# tasks to perform according to the specified "hz" value.
#
# By default "hz" is set to 10. Raising the value will use more CPU when
# Redis is idle, but at the same time will make Redis more responsive when
# there are many keys expiring at the same time, and timeouts may be
# handled with more precision.
#
# The range is between 1 and 500, however a value over 100 is usually not
# a good idea. Most users should use the default of 10 and raise this up to
# 100 only in environments where very low latency is required.
hz 10
# Normally it is useful to have an HZ value which is proportional to the
# number of clients connected. This is useful in order, for instance, to
# avoid too many clients are processed for each background task invocation
# in order to avoid latency spikes.
#
# Since the default HZ value by default is conservatively set to 10, Redis
# offers, and enables by default, the ability to use an adaptive HZ value
# which will 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.
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.
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.
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).
# 计数器衰减时间是键计数器除以2(如果值小于<= 10，则衰减)所必须经过的时间(以分钟为单位)。
# 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-decay-time的默认值是1。一个特殊的值0表示在每次扫描计数器时对其进行衰减。
# lfu-log-factor 10
# lfu-decay-time 1
########################### ACTIVE DEFRAGMENTATION #######################
#
# What is active defragmentation?
# -------------------------------
#
# Active (online) defragmentation allows a Redis server to compact the
# spaces left between small allocations and deallocations of data in memory,
# thus allowing to reclaim back memory.
#
# Fragmentation is a natural process that happens with every allocator (but
# less so with Jemalloc, fortunately) and certain workloads. Normally a server
# restart is needed in order to lower the fragmentation, or at least to flush
# away all the data and create it again. However thanks to this feature
# implemented by Oran Agra for Redis 4.0 this process can happen at runtime
# in 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
# activedefrag no
# Minimum amount of fragmentation waste to start active defrag
# active-defrag-ignore-bytes 100mb
# Minimum percentage of fragmentation to start active defrag
# active-defrag-threshold-lower 10
# Maximum percentage of fragmentation at which we use maximum effort
# active-defrag-threshold-upper 100
# Minimal effort for defrag in CPU percentage, to be used when the lower
# threshold is reached
# active-defrag-cycle-min 1
# Maximal effort for defrag in CPU percentage, to be used when the upper
# threshold is reached
# active-defrag-cycle-max 25
# Maximum number of set/hash/zset/list fields that will be processed from
# the main dictionary scan
# active-defrag-max-scan-fields 1000
# Jemalloc background thread for purging will be enabled by default
jemalloc-bg-thread yes
# It is possible to pin different threads and processes of Redis to specific
# CPUs in your system, in order to maximize the performances of the server.
# This is useful both in order to pin different Redis threads in different
# CPUs, but also in order to make sure that multiple Redis instances running
# in the same host will be pinned to different CPUs.
#
# Normally you can do this using the "taskset" command, however it is also
# possible to this via Redis configuration directly, both in Linux and FreeBSD.
#
# You can pin the server/IO threads, bio threads, aof rewrite child process, and
# the bgsave child process. The syntax to specify the cpu list is the same as
# the taskset command:
#
# Set redis server/io threads to cpu affinity 0,2,4,6:
# server_cpulist 0-7:2
#
# Set bio threads to cpu affinity 1,3:
# bio_cpulist 1,3
#
# Set aof rewrite child process to cpu affinity 8,9,10,11:
# aof_rewrite_cpulist 8-11
#
# Set bgsave child process to cpu affinity 1,10,11
# bgsave_cpulist 1,10-11