Redis 配置文件 详解

# Redis configuration file example# 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:# 内存大小的配置，下面是内存大小配置的转换方式## 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.# 内存大小的配置，不区分大小写################################## INCLUDES #################################### Include one or more other config files here.  This is useful if you# have a standard template that goes to all Redis server 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.## include /path/to/local.conf# include /path/to/other.conf# 当配置多个redis时，可能大部分配置一样，而对于不同的redis，只有少部分配置需要定制# 就可以配置一个公共的模板配置。# 对于具体的reids，只需设置少量的配置，并用include把模板配置包含进来即可。## 值得注意的是，对于同一个配置项，redis只对最后一行的有效# 所以为避免模板配置覆盖当前配置，应在配置文件第一行使用include# 当然，如果模板配置的优先级比较高，就在配置文件最后一行使用include################################ 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.# yes为使用守护进程，此时redis的进程ID会被写进 pidfile的配置中daemonize yes# When running daemonized, Redis writes a pid file in /var/run/redis.pid by# default. You can specify a custom pid file location here.# 当redis以守护进程的方式启动时，redis的进程ID将会写在这个文件中pidfile /var/run/redis.pid# Accept connections on the specified port, default is 6379.# If port 0 is specified Redis will not listen on a TCP socket.# redis 启动的端口。【应该知道redis是服务端吧】port 6379# TCP listen() backlog.## In high requests-per-second environments you need an high backlog in order# to avoid slow clients connections issues. Note that the Linux kernel# will silently truncate it to the value of /proc/sys/net/core/somaxconn so# make sure to raise both the value of somaxconn and tcp_max_syn_backlog# in order to get the desired effect.# 最大链接缓冲池的大小，这里应该是指的未完成链接请求的数量#（测试值为1时，仍可以有多个链接）# 但该值与listen函数中的backlog意义应该是相同的，源码中该值就是被用在了listen函数中# 该值同时受/proc/sys/net/core/somaxconn 和 tcp_max_syn_backlog（/etc/sysctl.conf中配置）的限制# tcp_max_syn_backlog 指的是未完成链接的数量tcp-backlog 511# By default Redis listens for connections from all the network interfaces# available on the server. It is possible to listen to just one or multiple# interfaces using the "bind" configuration directive, followed by one or# more IP addresses.# 绑定ip，指定ip可以连接到redis## Examples:## bind 192.168.1.100 10.0.0.1# bind 127.0.0.1# 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.## 这个应该就是以文件形式创建的socket# unixsocket /tmp/redis.sock# unixsocketperm 755# Close the connection after a client is idle for N seconds (0 to disable)# 超时断链机制，如果一个链接在N秒内没有任何操作，则断开该链接# N为0时，该机制失效timeout 0# TCP keepalive.## If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence# of communication. This is useful for two reasons:## 1) Detect dead peers.# 2) Take the connection alive from the point of view of network#    equipment in the middle.## On Linux, the specified value (in seconds) is the period used to send ACKs.# Note that to close the connection the double of the time is needed.# On other kernels the period depends on the kernel configuration.# 就像心跳检测一样，检查链接是否保持正常，同时也可以保持正常链接的通信# 建议值为60## A reasonable value for this option is 60 seconds.tcp-keepalive 0# 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)# 日志级别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# 日志存放路径，默认是输出到标准输出，但当以守护进程方式启动时，默认输出到/dev/null(传说中的linux黑洞)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.# yes 表示将日志写到系统日志中# syslog-enabled no# Specify the syslog identity.# 当syslog-enabled为yes时，指定系统日志的标示为 redis# syslog-ident redis# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.# 指定系统日志的设备# syslog-facility local0# Set the number of databases. The default database is DB 0, you can select# a different one on a per-connection basis using SELECT <dbid> where# dbid is a number between 0 and 'databases'-1# redis的数据库格式，默认16个(0~15)，默认使用第0个。databases 16################################ SNAPSHOTTING  ################################## Save the DB on disk:##   save <seconds> <changes>##   Will save the DB if both the given number of seconds and the given#   number of write operations against the DB occurred.# 快照，即将数据写到硬盘上，在<seconds>秒内，至少有<changes>次写入数据库操作# 则会将数据写入硬盘一次。# 将save行注释掉则永远不会写入硬盘# save "" 表示删除所有的快照点##   In the example below the behaviour will be to save:#   after 900 sec (15 min) if at least 1 key changed#   after 300 sec (5 min) if at least 10 keys changed#   after 60 sec if at least 10000 keys changed##   Note: you can disable saving at all commenting all the "save" lines.##   It is also possible to remove all the previously configured save#   points by adding a save directive with a single empty string argument#   like in the following example:##   save ""save 900 1save 300 10save 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.# 当做快照失败的时候，redis会停止继续向其写入数据，保证第一时间发现redis快照出现问题# 当然，通过下面配置为 no，即使redis快照失败，也能继续向redis写入数据stop-writes-on-bgsave-error yes# Compress string objects using LZF when dump .rdb databases?# For default that's set to 'yes' as it's almost always a win.# If you want to save some CPU in the saving child set it to 'no' but# the dataset will likely be bigger if you have compressible values or keys.# 快照的时候，是否用LZF压缩，使用压缩会占一定的cpu，但不使用压缩，快照会很大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.# 数据校验，快照末尾会存放一个校验值，保证数据的准确性# 但数据校验会使性能下降约10%，默认开启校验rdbchecksum yes# The filename where to dump the DB# 快照的名字dbfilename dump.rdb# 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.# # 快照存放的目录# linux root下测试，会发现该进程会在当前目录下创建一个dump.rdb# 但快照却放在了根目录/下，重启的时候，是不会从快照中恢复数据的# 当把根目录下的dump.rdb文件拷贝到当前目录的时候，再次启动，就会从快照中恢复数据# 而且以后的快照也都在当前目录的dump.rdb中做操作## 值得一提的是，快照是异步方式的，如果在还未达到快照的时候，修改了数据，而且redis发生问题crash了# 那么中间的修改数据是不会被保存到dump.rdb快照中的# 解决办法就是用Append Only Mode的同步模式(下面将会有该配置项)# 将会把每个操作写到Append Only File中，该文件也存放于当前配置的目录# 建议使用绝对路径！！！# dir ./################################# REPLICATION ################################## Master-Slave replication. Use slaveof to make a Redis instance a copy of# another Redis server. Note that the configuration is local to the slave# so for example it is possible to configure the slave to save the DB with a# different interval, or to listen to another port, and so on.## 主从复制，类似于双机备份。# 配置需指定主机的ip 和port# slaveof <masterip> <masterport># If the master is password protected (using the "requirepass" configuration# directive below) it is possible to tell the slave to authenticate before# starting the replication synchronization process, otherwise the master will# refuse the slave request.## 如果主机redis需要密码，则指定密码# 密码配置在下面安全配置中# masterauth <master-password># When a slave loses its connection with the master, or when the replication# is still in progress, the slave can act in two different ways:## 1) if slave-serve-stale-data is set to 'yes' (the default) the slave will#    still reply to client requests, possibly with out of date data, or the#    data set may just be empty if this is the first synchronization.## 2) if slave-serve-stale-data is set to 'no' the slave will reply with#    an error "SYNC with master in progress" to all the kind of commands#    but to INFO and SLAVEOF.## 当从机与主机断开时，即同步出现问题的时候，从机有两种处理方式# yes, 继续响应客户端请求，但可能有脏数据（过期数据、空数据等）# no，对客户端的请求统一回复为“SYNC with master in progress”，除了INFO和SLAVEOF命令slave-serve-stale-data yes# You can configure a slave instance to accept writes or not. Writing against# a slave instance may be useful to store some ephemeral data (because data# written on a slave 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 slaves are read-only.## Note: read only slaves 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 slave 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 slaves using 'rename-command' to shadow all the# administrative / dangerous commands.# slave只读选项，设置从机只读（默认）。# 即使设置可写，当下一次从主机上同步数据，仍然会删除当前从机上写入的数据# 【待测试】：主机与从机互为slave会出现什么情况？# 【预期三种结果】：1. 提示报错 2. 主从服务器数据不可控 3. 一切正常slave-read-only yes# Slaves send PINGs to server in a predefined interval. It's possible to change# this interval with the repl_ping_slave_period option. The default value is 10# seconds.## 从服务器向主服务器发送心跳包，默认10发送一次# repl-ping-slave-period 10# The following option sets the replication timeout for:## 1) Bulk transfer I/O during SYNC, from the point of view of slave.# 2) Master timeout from the point of view of slaves (data, pings).# 3) Slave 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-slave-period otherwise a timeout will be detected# every time there is low traffic between the master and the slave.## 超时响应时间，值必须比repl-ping-slave-period大# 批量数据传输超时、ping超时# repl-timeout 60# Disable TCP_NODELAY on the slave socket after SYNC?## If you select "yes" Redis will use a smaller number of TCP packets and# less bandwidth to send data to slaves. But this can add a delay for# the data to appear on the slave side, up to 40 milliseconds with# Linux kernels using a default configuration.## If you select "no" the delay for data to appear on the slave 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 slaves are many hops away, turning this to "yes" may# be a good idea.# 主从同步是否延迟# yes 有延迟，约40毫秒（linux kernel的默认配置），使用较少的数据包，较小的带宽# no 无延迟（减少延迟），但需要更大的带宽repl-disable-tcp-nodelay no# Set the replication backlog size. The backlog is a buffer that accumulates# slave data when slaves are disconnected for some time, so that when a slave# wants to reconnect again, often a full resync is not needed, but a partial# resync is enough, just passing the portion of data the slave missed while# disconnected.## The biggest the replication backlog, the longer the time the slave can be# disconnected and later be able to perform a partial resynchronization.## The backlog is only allocated once there is at least a slave connected.## 默认情况下，当slave重连的时候，会进行全量数据同步# 但实际上slave只需要部分同步即可，这个选项设置部分同步的大小# 设置值越大，同步的时间就越长# repl-backlog-size 1mb# After a master has no longer connected slaves 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 slave disconnected, for# the backlog buffer to be freed.## A value of 0 means to never release the backlog.## 主机的后台日志释放时间，即当没有slave连接时，过多久释放后台日志# 0表示不释放# repl-backlog-ttl 3600# The slave priority is an integer number published by Redis in the INFO output.# It is used by Redis Sentinel in order to select a slave to promote into a# master if the master is no longer working correctly.## A slave with a low priority number is considered better for promotion, so# for instance if there are three slaves with priority 10, 100, 25 Sentinel will# pick the one with priority 10, that is the lowest.## However a special priority of 0 marks the slave as not able to perform the# role of master, so a slave with priority of 0 will never be selected by# Redis Sentinel for promotion.## By default the priority is 100.# 当主机crash的时候，在从机中选择一台作为主机，数字越小，优先级越高# 0 表示永远不作为主机，默认值是100slave-priority 100# It is possible for a master to stop accepting writes if there are less than# N slaves connected, having a lag less or equal than M seconds.## The N slaves need to be in "online" state.## The lag in seconds, that must be <= the specified value, is calculated from# the last ping received from the slave, that is usually sent every second.## This option does not GUARANTEES that N replicas will accept the write, but# will limit the window of exposure for lost writes in case not enough slaves# are available, to the specified number of seconds.## For example to require at least 3 slaves with a lag <= 10 seconds use:## 当slave数量小于min-slaves-to-write，且延迟小于等于min-slaves-max-lag时，# 主机停止写入操作# 0表示禁用# 默认min-slaves-to-write为0，即禁用。min-slaves-max-lag为10# min-slaves-to-write 3# min-slaves-max-lag 10## Setting one or the other to 0 disables the feature.## By default min-slaves-to-write is set to 0 (feature disabled) and# min-slaves-max-lag is set to 10.################################## SECURITY #################################### Require clients to issue AUTH <PASSWORD> before processing any other# commands.  This might be useful in environments in which you do not trust# others with access to the host running redis-server.## This should stay commented out for backward compatibility and because most# people do not need auth (e.g. they run their own servers).# # Warning: since Redis is pretty fast an outside user can try up to# 150k passwords per second against a good box. This means that you should# use a very strong password otherwise it will be very easy to break.## redis密码，默认不配置，即无密码# 这里注意，如果设置了密码，应该设置一个复杂度比较高的密码# 因为redis的速度很快，每秒可以尝试150k次的密码测试，很容易对其进行暴力破解（跑码）。# 疑问：这里为什么不设置一个针对主机的测试次数限制的，例如每10次，则禁止建立连接1个小时！# requirepass foobared# Command renaming.## 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.## 命令重命名，将命令重命名为另一个字符串标识# 如果命令为空串("")，则会彻底禁用该命令# 命令重命名，会对写AOF(Append of file)文件、slave从机造成一些问题# 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 slaves may cause problems.################################### LIMITS ##################################### 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'.## 这只redis的最大连接数目，默认设置为10000个客户端# 当超过限制时，将段开新的连接，并响应“max number of clients reached”# maxclients 10000# Don't use more memory than 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 cache, or to set# a hard memory limit for an instance (using the 'noeviction' policy).## WARNING: If you have slaves attached to an instance with maxmemory on,# the size of the output buffers needed to feed the slaves 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 slaves 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 slaves attached it is suggested that you set a lower# limit for maxmemory so that there is some free RAM on the system for slave# output buffers (but this is not needed if the policy is 'noeviction').## redis的最大内存限制，如果达到最大内存，会按照下面的maxmemory-policy进行清除# 如果不能再清除或者maxmemory-policy为noeviction，则对于需要增加空间的操作，将会返回错误# maxmemory <bytes># MAXMEMORY POLICY: how Redis will select what to remove when maxmemory# is reached. You can select among five behaviors:# # volatile-lru -> remove the key with an expire set using an LRU algorithm# allkeys-lru -> remove any key accordingly to the LRU algorithm# volatile-random -> remove a random key with 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 expire at all, just return an error on write operations# # Note: with any of the above policies, Redis will return an error on write#       operations, when there are not suitable keys for eviction.##       At the date of writing this 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:## 内存删除策略，默认volatile-lru，利用LRU算法，删除过期的key# maxmemory-policy volatile-lru# LRU and minimal TTL algorithms are not precise algorithms but approximated# algorithms (in order to save memory), so you can select as well the sample# size to check. For instance for default Redis will check three keys and# pick the one that was used less recently, you can change the sample size# using the following configuration directive.## LRU算法与最小TTL算法只是相对精确的算法，并不是绝对精确的算法# 为了更精确，可以设置样本个数# 比如设置3个样本，redis会选取三个key，并选择删除那个上次使用时间最远的# maxmemory-samples 3############################## APPEND ONLY MODE ################################ By default Redis asynchronously dumps the dataset on disk. This mode is# good enough in many applications, but an issue with the Redis process or# a power outage may result into a few minutes of writes lost (depending on# the configured save points).## The Append Only File is an alternative persistence mode that provides# much better durability. For instance using the default data fsync policy# (see later in the config file) Redis can lose just one second of writes in a# dramatic event like a server power outage, or a single write if something# wrong with the Redis process itself happens, but the operating system is# still running correctly.## AOF and RDB persistence can be enabled at the same time without problems.# If the AOF is enabled on startup Redis will load the AOF, that is the file# with the better durability guarantees.## Please check http://redis.io/topics/persistence for more information.# 将对redis所有的操作都保存到AOF文件中# 因为dump.rdb是异步的，在下次快照到达之前，如果出现crash等问题，会造成数据丢失# 而AOF文件时同步记录的，所以会完整的恢复数据appendonly no# The name of the append only file (default: "appendonly.aof")# AOF文件的名字appendfilename "appendonly.aof"# The fsync() call tells the Operating System to actually write data on disk# instead to wait for more data in the output buffer. Some OS will really flush # data on disk, some other OS will just try to do it ASAP.## Redis supports three different modes:## no: don't fsync, just let the OS flush the data when it wants. Faster.# always: fsync after every write to the append only log . Slow, Safest.# everysec: fsync only one time every second. Compromise.## The default is "everysec", as that's usually the right compromise between# speed and data safety. It's up to you to understand if you can relax this to# "no" that will let the operating system flush the output buffer when# it wants, for better performances (but if you can live with the idea of# some data loss consider the default persistence mode that's snapshotting),# or on the contrary, use "always" that's very slow but a bit safer than# everysec.## More details please check the following article:# http://antirez.com/post/redis-persistence-demystified.html## If unsure, use "everysec".# redis的数据同步方式，三种# no，redis本身不做同步，由OS来做。redis的速度会很快# always，在每次写操作之后，redis都进行同步，即写入AOF文件。redis会变慢，但是数据更安全# everysec，折衷考虑，每秒同步一次数据。【默认】# appendfsync alwaysappendfsync 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.# redis的同步方式中，always和everysec，快照和写AOF可能会执行大量的硬盘I/O操作，# 而在一些Linux的配置中，redis会阻塞很久，而redis本身并没有很好的解决这一问题。# 为了缓和这一问题，redis提供no-appendfsync-on-rewrite选项，# 即当有另外一个进程在执行保存操作的时候，redis采用no的同步方式。# 最坏情况下会有延迟30秒的同步延迟。# 如果你觉得这样做会有潜在危险，则请将该选项改为yes。否则就保持默认值no（基于稳定性考虑）。no-appendfsync-on-rewrite no# Automatic rewrite of the append only file.# Redis is able to automatically rewrite the log file implicitly calling# BGREWRITEAOF when the AOF log size grows by the specified percentage.# # This is how it works: Redis remembers the size of the AOF file after the# latest rewrite (if no rewrite has happened since the restart, the size of# the AOF at startup is used).## This base size is compared to the current size. If the current size is# bigger than the specified percentage, the rewrite is triggered. Also# you need to specify a minimal size for the AOF file to be rewritten, this# is useful to avoid rewriting the AOF file even if the percentage increase# is reached but it is still pretty small.## Specify a percentage of zero in order to disable the automatic AOF# rewrite feature.# 自动重写AOF文件# 当AOF日志文件大小增长到指定百分比时，redis会自动隐式调用BGREWRITEAOF来重写AOF文件# redis会记录上次重写AOF文件之后的大小，# 如果当前文件大小增加了auto-aof-rewrite-percentage，则会触发重写AOF日志功能# 当然如果文件过小，比如小于auto-aof-rewrite-min-size这个大小，是不会触发重写AOF日志功能的# auto-aof-rewrite-percentage为0时，禁用重写功能auto-aof-rewrite-percentage 100auto-aof-rewrite-min-size 64mb################################ LUA SCRIPTING  ################################ Max execution time of a Lua script in milliseconds.## If the maximum execution time is reached Redis will log that a script is# still in execution after the maximum allowed time and will start to# reply to queries with an error.## When a long running script exceed 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 commands was# already issue by the script but the user don't want to wait for the natural# termination of the script.## Set it to 0 or a negative value for unlimited execution without warnings.# LUA脚本的最大执行时间（单位是毫秒），默认5000毫秒，即5秒# 如果LUA脚本执行超过这个限制，可以调用SCRIPT KILL和SHUTDOWN NOSAVE命令。# SCRIPT KILL可以终止脚本执行# SHUTDOWN NOSAVE关闭服务，防止LUA脚本的写操作发生# 该值为0或者负数，表示没有限制时间lua-time-limit 5000################################## SLOW LOG #################################### The Redis Slow Log is a system to log queries that exceeded a specified# execution time. The execution time does not include the I/O operations# like talking with the client, sending the reply and so forth,# but just the time needed to actually execute the command (this is the only# stage of command execution where the thread is blocked and can not serve# other requests in the meantime).# # You can configure the slow log with two parameters: one tells Redis# what is the execution time, in microseconds, to exceed in order for the# command to get logged, and the other parameter is the length of the# slow log. When a new command is logged the oldest one is removed from the# queue of logged commands.# 记录执行比较慢的命令# 执行比较慢仅仅是指命令的执行时间，不包括客户端的链接与响应等时间# slowlog-log-slower-than 设定这个慢的时间，单位是微妙，即1000000表示1秒，0表示所有命令都记录，负数表示不记录# slowlog-max-len表示记录的慢命令的个数，超过限制，则最早记录的命令会被移除# 命令的长度没有限制，但是会消耗内存，用SLOWLOG RESET来收回这些消耗的内存# The following time is expressed in microseconds, so 1000000 is equivalent# to one second. Note that a negative number disables the slow log, while# a value of zero forces the logging of every command.slowlog-log-slower-than 10000# There is no limit to this length. Just be aware that it will consume memory.# You can reclaim memory used by the slow log with SLOWLOG RESET.slowlog-max-len 128################################ LATENCY MONITOR ############################### The Redis latency monitoring subsystem samples different operations# at runtime in order to collect data related to possible sources of# latency of a Redis instance.## Via the LATENCY command this information is available to the user that can# print graphs and obtain reports.## The system only logs operations that were performed in a time equal or# greater than the amount of milliseconds specified via the# latency-monitor-threshold configuration directive. When its value is set# to zero, the latency monitor is turned off.## By default latency monitoring is disabled since it is mostly not needed# if you don't have latency issues, and collecting data has a performance# impact, that while very small, can be measured under big load. Latency# monitoring can easily be enalbed at runtime using the command# "CONFIG SET latency-monitor-threshold <milliseconds>" if needed.# 延迟监控器# redis延迟监控子系统在运行时，会抽样检测可能导致延迟的不同操作# 通过LATENCY命令可以打印相关信息和报告, 命令如下（摘自源文件注释）：# LATENCY SAMPLES: return time-latency samples for the specified event.# LATENCY LATEST: return the latest latency for all the events classes.# LATENCY DOCTOR: returns an human readable analysis of instance latency.# LATENCY GRAPH: provide an ASCII graph of the latency of the specified event.# # 系统只记录超过设定值的操作，单位是毫秒，0表示禁用该功能# 可以通过命令“CONFIG SET latency-monitor-threshold <milliseconds>” 直接设置而不需要重启redislatency-monitor-threshold 0############################# Event notification ############################### Redis can notify Pub/Sub clients about events happening in the key space.# This feature is documented at http://redis.io/topics/keyspace-events# # 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)#  A     Alias for g$lshzxe, so that the "AKE" string means all the events.##  The "notify-keyspace-events" takes as argument a string that is composed#  by zero or multiple characters. The empty string means that notifications#  are disabled at all.##  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.# 事件通知，当事件发生时，redis可以通知Pub/Sub客户端# 空串表示禁用事件通知# 注意：K和E至少要指定一个，否则不会有事件通知notify-keyspace-events ""############################### ADVANCED CONFIG ################################ Hashes are encoded using a memory efficient data structure when they have a# small number of entries, and the biggest entry does not exceed a given# threshold. These thresholds can be configured using the following directives.# 当hash数目比较少，并且最大元素没有超过给定值时，Hash使用比较有效的内存数据结构来存储。# 即ziplist的结构（压缩的双向链表），参考：http://blog.csdn.net/benbendy1984/article/details/7796956hash-max-ziplist-entries 512hash-max-ziplist-value 64# Similarly to hashes, small lists are also encoded in a special way in order# to save a lot of space. The special representation is only used when# you are under the following limits:# List配置同Hashlist-max-ziplist-entries 512list-max-ziplist-value 64# Sets have a special encoding in just one case: when a set is composed# of just strings that happens 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.# Sets的元素如果全部是整数（10进制），且为64位有符号整数，则采用特殊的编码方式。# 其元素个数限制配置如下：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:# sorted set 同Hash和Listzset-max-ziplist-entries 128zset-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.# 关于HyperLogLog的介绍：http://www.redis.io/topics/data-types-intro#hyperloglogs# HyperLogLog稀疏表示限制设置，如果其值大于16000，则仍然采用稠密表示，因为这时稠密表示更能有效使用内存# 建议值为3000hll-sparse-max-bytes 3000# 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# active rehashing 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 form time to time# to queries with 2 milliseconds delay.## use "activerehashing yes" if you don't have such hard requirements but# want to free memory asap when possible.# 每100毫秒，redis将用1毫秒的时间对Hash表进行重新Hash。# 采用懒惰Hash方式：操作Hash越多，则重新Hash的可能越多，若根本就不操作Hash，则不会重新Hash# 默认每秒10次重新hash主字典，释放可能释放的内存# 重新hash会造成延迟，如果对延迟要求较高，则设为no，禁止重新hash。但可能会浪费很多内存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# slave  -> slave clients# pubsub -> clients subscribed to at least one pubsub channel or pattern## The syntax of every client-output-buffer-limit directive is the following:## 客户端输出缓冲区限制，当客户端从服务端的读取速度不够快时，则强制断开# 三种不同的客户端类型：normal、salve、pubsub，语法如下：# 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 slave clients, since# subscribers and slaves receive data in a push fashion.## Both the hard or the soft limit can be disabled by setting them to zero.# 当达到硬限制，或者达到软限制且持续了算限制秒数，则立即与客户端断开# 限制设为0表示禁止该功能# 普通用户默认不限制client-output-buffer-limit normal 0 0 0client-output-buffer-limit slave 256mb 64mb 60client-output-buffer-limit pubsub 32mb 8mb 60# 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 accordingly 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.# redis调用内部函数执行的后台任务的频率# 后台任务比如：清除过期数据、客户端超时链接等# 默认为10，取值范围1~500,# 对延迟要求很低的可以设置超过100以上hz 10# 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.# 当修改AOF文件时，该设置为yes，则每生成32MB的数据，就进行同步aof-rewrite-incremental-fsync yes