# Note on units: when memory size is needed, it is possible to specify
# it in the usual form of 1k 5GB 4M and so forth:
#
# 1k => 1000 bytes
# 1kb => 1024 bytes
# 1m => 1000000 bytes
# 1mb => 1024*1024 bytes
# 1g => 1000000000 bytes
# 1gb => 1024*1024*1024 bytes
#
# units are case insensitive so 1GB 1Gb 1gB are all the same.
################################## INCLUDES ###################################
# Include one or more other config files here. This is useful if you
# have a standard template that goes to all Redis servers but also need
# to customize a few per-server settings. Include files can include
# other files, so use this wisely.
#
# Note that option "include" won't be rewritten by command "CONFIG REWRITE"
# from admin or Redis Sentinel. Since Redis always uses the last processed
# line as value of a configuration directive, you'd better put includes
# at the beginning of this file to avoid overwriting config change at runtime.
#
# If instead you are interested in using includes to override configuration
# options, it is better to use include as the last line.
#
# include /path/to/local.conf
# include /path/to/other.conf
# IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
# JUST COMMENT OUT THE FOLLOWING LINE.
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
bind 127.0.0.1 ::1
....
# TCP listen() backlog.
#
# In high requests-per-second environments you need a high backlog in order
# to avoid slow clients connection issues. Note that the Linux kernel
# will silently truncate it to the value of /proc/sys/net/core/somaxconn so
# make sure to raise both the value of somaxconn and tcp_max_syn_backlog
# in order to get the desired effect.
tcp-backlog 511
...
# 空闲多少时间自动关闭，0就一直连接
# Close the connection after a client is idle for N seconds (0 to disable)
timeout 0
# TCP keepalive.
#
# If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence
# of communication. This is useful for two reasons:
#
# 1) Detect dead peers.
# 2) Force network equipment in the middle to consider the connection to be
# alive.
#
# On Linux, the specified value (in seconds) is the period used to send ACKs.
# Note that to close the connection the double of the time is needed.
# On other kernels the period depends on the kernel configuration.
#
# A reasonable value for this option is 300 seconds, which is the new
# Redis default starting with Redis 3.2.1.
tcp-keepalive 300
Tcp-backlog，设置tcp的backlog，backlog其实就是一个连接队列，backlog队列总和=未完成三次握手队列+已经完成三次握手队列。在高并发环境下你需要一个高的backlog值来避免慢客户端连接问题。
################################# 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 /usr/local/var/run/redis.pid when daemonized.
# When Redis is supervised by upstart or systemd, this parameter has no impact.
# daemonize no
# 修改为yes
daemonize yes
# If you run Redis from upstart or systemd, Redis can interact with your
# supervision tree. Options:
# supervised no - no supervision interaction
# supervised upstart - signal upstart by putting Redis into SIGSTOP mode
# requires "expect stop" in your upstart job config
# supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET
# on startup, and updating Redis status on a regular
# basis.
# supervised auto - detect upstart or systemd method based on
# UPSTART_JOB or NOTIFY_SOCKET environment variables
# Note: these supervision methods only signal "process is ready."
# They do not enable continuous pings back to your supervisor.
#
# The default is "no". To run under upstart/systemd, you can simply uncomment
# the line below:
#
# supervised auto
# If a pid file is specified, Redis writes it where specified at startup
# and removes it at exit.
#
# When the server runs non daemonized, no pid file is created if none is
# specified in the configuration. When the server is daemonized, the pid file
# is used even if not specified, defaulting to "/usr/local/var/run/redis.pid".
#
# Creating a pid file is best effort: if Redis is not able to create it
# nothing bad happens, the server will start and run normally.
#
# Note that on modern Linux systems "/run/redis.pid" is more conforming
# and should be used instead.
# 进程管道ID文件，运行起来的时候，如果你没有指定路径，那么就默认该路径
pidfile /var/run/redis_6379.pid
# Redis日志级别（4个级别）根据实际情况进行使用
# Specify the server verbosity level.
# This can be one of:
# debug (a lot of information, useful for development/testing)
# verbose (many rarely useful info, but not a mess like the debug level)
# notice (moderately verbose, what you want in production probably)
# warning (only very important / critical messages are logged)
loglevel notice
# 日志名字
# Specify the log file name. Also the empty string can be used to force
# Redis to log on the standard output. Note that if you use standard
# output for logging but daemonize, logs will be sent to /dev/null
logfile ""
# 系统日志默认关闭的
# To enable logging to the system logger, just set 'syslog-enabled' to yes,
# and optionally update the other syslog parameters to suit your needs.
# syslog-enabled no
# 如果开启就以Redis开头
# Specify the syslog identity.
# syslog-ident redis
# 指定syslog，值可以是USER或LOCALO-LOCAL7
# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
# syslog-facility local0
# To disable the built in crash log, which will possibly produce cleaner core
# dumps when they are needed, uncomment the following:
#
# crash-log-enabled no
# To disable the fast memory check that's run as part of the crash log, which
# will possibly let redis terminate sooner, uncomment the following:
#
# crash-memcheck-enabled no
# Redis默认16库
# Set the number of databases. The default database is DB 0, you can select
# a different one on a per-connection basis using SELECT <dbid> where
# dbid is a number between 0 and 'databases'-1
databases 16
# By default Redis shows an ASCII art logo only when started to log to the
# standard output and if the standard output is a TTY and syslog logging is
# disabled. Basically this means that normally a logo is displayed only in
# interactive sessions.
# However it is possible to force the pre-4.0 behavior and always show a
# ASCII art logo in startup logs by setting the following option to yes.
always-show-logo no
# By default, Redis modifies the process title (as seen in 'top' and 'ps') to
# provide some runtime information. It is possible to disable this and leave
# the process name as executed by setting the following to no.
set-proc-title yes
# When changing the process title, Redis uses the following template to construct
# the modified title.
#
# Template variables are specified in curly brackets. The following variables are
# supported:
#
# {title} Name of process as executed if parent, or type of child process.
# {listen-addr} Bind address or '*' followed by TCP or TLS port listening on, or
# Unix socket if only that's available.
# {server-mode} Special mode, i.e. "[sentinel]" or "[cluster]".
# {port} TCP port listening on, or 0.
# {tls-port} TLS port listening on, or 0.
# {unixsocket} Unix domain socket listening on, or "".
# {config-file} Name of configuration file used.
#
proc-title-template "{title} {listen-addr} {server-mode}"
################################ SNAPSHOTTING ################################
# Save the DB to disk.
#
# 持久化保存命令格式：save [多少秒] [改变次数]
# save <seconds> <changes>
#
# Redis will save the DB if both the given number of seconds and the given
# number of write operations against the DB occurred.
#
# Snapshotting can be completely disabled with a single empty string argument
# as in following example:
#
# 开启就是禁用的意思
# save ""
#
# 1、3600秒内(1小时)，只要Redis有 1 key被改动1过，就出发持久化机制
# 2、300秒(5分钟)key被改动过100次
# 3、60秒(1分钟)，有10000次变更，就触发持久化
# Unless specified otherwise, by default Redis will save the DB:
# * After 3600 seconds (an hour) if at least 1 key changed
# * After 300 seconds (5 minutes) if at least 100 keys changed
# * After 60 seconds if at least 10000 keys changed
#
# You can set these explicitly by uncommenting the three following lines.
#
# 我们可以根据需求要设置，这里假如模拟2分钟内修改10，就让他触发持久化
save 120 10
# save 3600 1
# save 300 100
# save 60 10000
# By default Redis will stop accepting writes if RDB snapshots are enabled
# (at least one save point) and the latest background save failed.
# This will make the user aware (in a hard way) that data is not persisting
# on disk properly, otherwise chances are that no one will notice and some
# disaster will happen.
#
# If the background saving process will start working again Redis will
# automatically allow writes again.
#
# However if you have setup your proper monitoring of the Redis server
# and persistence, you may want to disable this feature so that Redis will
# continue to work as usual even if there are problems with disk,
# permissions, and so forth.
stop-writes-on-bgsave-error yes
# Compress string objects using LZF when dump .rdb databases?
# By default compression is enabled as it's almost always a win.
# If you want to save some CPU in the saving child set it to 'no' but
# the dataset will likely be bigger if you have compressible values or keys.
rdbcompression yes
# Since version 5 of RDB a CRC64 checksum is placed at the end of the file.
# This makes the format more resistant to corruption but there is a performance
# hit to pay (around 10%) when saving and loading RDB files, so you can disable it
# for maximum performances.
#
# RDB files created with checksum disabled have a checksum of zero that will
# tell the loading code to skip the check.
rdbchecksum yes
# Enables or disables full sanitation checks for ziplist and listpack etc when
# loading an RDB or RESTORE payload. This reduces the chances of a assertion or
# crash later on while processing commands.
# Options:
# no - Never perform full sanitation
# yes - Always perform full sanitation
# clients - Perform full sanitation only for user connections.
# Excludes: RDB files, RESTORE commands received from the master
# connection, and client connections which have the
# skip-sanitize-payload ACL flag.
# The default should be 'clients' but since it currently affects cluster
# resharding via MIGRATE, it is temporarily set to 'no' by default.
#
# sanitize-dump-payload no
# The filename where to dump the DB
dbfilename dump.rdb
# Remove RDB files used by replication in instances without persistence
# enabled. By default this option is disabled, however there are environments
# where for regulations or other security concerns, RDB files persisted on
# disk by masters in order to feed replicas, or stored on disk by replicas
# in order to load them for the initial synchronization, should be deleted
# ASAP. Note that this option ONLY WORKS in instances that have both AOF
# and RDB persistence disabled, otherwise is completely ignored.
#
# An alternative (and sometimes better) way to obtain the same effect is
# to use diskless replication on both master and replicas instances. However
# in the case of replicas, diskless is not always an option.
rdb-del-sync-files no
# The working directory.
#
# The DB will be written inside this directory, with the filename specified
# above using the 'dbfilename' configuration directive.
#
# The Append Only File will also be created inside this directory.
#
# Note that you must specify a directory here, not a file name.
dir /usr/local/var/db/redis/
Config get requirepass #查看密码
Config set requirepass #设置密码
config get dir #查看路径（启动如果指定Redis配置文件，路径就不一样的）
################################## SECURITY ###################################
...
# IMPORTANT NOTE: starting with Redis 6 "requirepass" is just a compatibility
# layer on top of the new ACL system. The option effect will be just setting
# the password for the default user. Clients will still authenticate using
# AUTH <password> as usually, or more explicitly with AUTH default <password>
# if they follow the new protocol: both will work.
#
# The requirepass is not compatable with aclfile option and the ACL LOAD
# command, these will cause requirepass to be ignored.
#
# requirepass foobared
...
################################### CLIENTS ####################################
# Set the max number of connected clients at the same time. By default
# this limit is set to 10000 clients, however if the Redis server is not
# able to configure the process file limit to allow for the specified limit
# the max number of allowed clients is set to the current file limit
# minus 32 (as Redis reserves a few file descriptors for internal uses).
#
# Once the limit is reached Redis will close all the new connections sending
# an error 'max number of clients reached'.
#
# IMPORTANT: When Redis Cluster is used, the max number of connections is also
# shared with the cluster bus: every node in the cluster will use two
# connections, one incoming and another outgoing. It is important to size the
# limit accordingly in case of very large clusters.
#
# 最大可以连接10000
# maxclients 10000
面试题：Redis是内存数据库，它的缓存过期策略你是如何理解和配置的？
内存是有限的，假如现在存10000个数据，但是发现100个已经两个月都没有用过，而且数据特别大，这是我们就需要最大内存策略或者过期策略/缓存策略。
《最大记忆策略： 雷迪斯如何选择在最大记忆时删除什么？已到达。您可以从以下行为中选择一个：》
############################## MEMORY MANAGEMENT ################################
# In short... if you have replicas attached it is suggested that you set a lower
# limit for maxmemory so that there is some free RAM on the system for replica
# output buffers (but this is not needed if the policy is 'noeviction').
#
# maxmemory <bytes>
# 《最大记忆策略： Redis如何选择在最大记忆时删除什么？已到达。您可以从以下行为中选择一个：》
# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
# is reached. You can select one from the following behaviors:
#
# 1、volatile-lru：使用LRU算法移除key，只对设置了过期时间的键
# 2、allkeys-lru：使用LUR算法移除key
# 3、volatile-random：在过期集合中移除随机key
# 4、allkeys-random：移除随机的key
# 5、volatile-ttl：移除那些TTL值最小的key，即那些最近要过期的key
# 6、noeviction：不进行移除，针对写操作，只是返回错误信息（默认使用，实际需要修改的）
# volatile-lru -> Evict using approximated LRU, only keys with an expire set.
# allkeys-lru -> Evict any key using approximated LRU.
# volatile-lfu -> Evict using approximated LFU, only keys with an expire set.
# allkeys-lfu -> Evict any key using approximated LFU.
# volatile-random -> Remove a random key having an expire set.
# allkeys-random -> Remove a random key, any key.
# volatile-ttl -> Remove the key with the nearest expire time (minor TTL)
# noeviction -> Don't evict anything, just return an error on write operations.
#
# LRU means Least Recently Used
# LFU means Least Frequently Used
#
# Both LRU, LFU and volatile-ttl are implemented using approximated
# randomized algorithms.
#
# Note: with any of the above policies, when there are no suitable keys for
# eviction, Redis will return an error on write operations that require
# more memory. These are usually commands that create new keys, add data or
# modify existing keys. A few examples are: SET, INCR, HSET, LPUSH, SUNIONSTORE,
# SORT (due to the STORE argument), and EXEC (if the transaction includes any
# command that requires memory).
#
# The default is:
#
# 默认《永不过期策略》
# maxmemory-policy noeviction
# LRU, LFU and minimal TTL algorithms are not precise algorithms but approximated
# algorithms (in order to save memory), so you can tune it for speed or
# accuracy. By default Redis will check five keys and pick the one that was
# used least recently, you can change the sample size using the following
# configuration directive.
#
# The default of 5 produces good enough results. 10 Approximates very closely
# true LRU but costs more CPU. 3 is faster but not very accurate.
#
# 设置样本数量，LRU算法和最小TTL算法都并非是精确的算法，而是估值算法，所以你可以设置样本的大小，redis默认会检查这么多个key并选择其中LRU的那个。默认5个
# maxmemory-samples 5
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