# 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 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的数据库数量，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 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. # # 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 ./
# 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100 slave-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.
# 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.
# 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 <1024*1024*1024> maxmemory 200mb
# 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 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. # 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
# 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
# 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
# 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redis
# 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 ""
# 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/7796956 hash-max-ziplist-entries 512 hash-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Hash list-max-ziplist-entries 512 list-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List 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. # 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3000 hll-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 0 client-output-buffer-limit slave 256mb 64mb 60 client-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