Redis(3) 配置文件 redis.conf

时间:2021-08-01 20:35:05

Redis.conf 配置详解:

Redis(3) 配置文件 redis.confRedis(3) 配置文件 redis.conf
   1 # Redis configuration file example.
   2 #
   3 # Note that in order to read the configuration file, Redis must be
   4 # started with the file path as first argument:
   5 #
   6 # 启动redis服务器时,加载配置文件, 必须用配置文件路径作为第一参数
   7 # ./redis-server /path/to/redis.conf
   8 
   9 # Note on units: when memory size is needed, it is possible to specify
  10 # it in the usual form of 1k 5GB 4M and so forth:
  11 #
  12 # 配置大小单位,开头定义了一些基本的度量单位,只支持bytes,不支持bit
  13 # 1k => 1000 bytes
  14 # 1kb => 1024 bytes
  15 # 1m => 1000000 bytes
  16 # 1mb => 1024*1024 bytes
  17 # 1g => 1000000000 bytes
  18 # 1gb => 1024*1024*1024 bytes
  19 #
  20 # units are case insensitive so 1GB 1Gb 1gB are all the same.
  21 # 大小写不敏感
  22 
  23 ################################## INCLUDES ###################################
  24 
  25 # Include one or more other config files here.  This is useful if you
  26 # have a standard template that goes to all Redis servers but also need
  27 # to customize a few per-server settings.  Include files can include
  28 # other files, so use this wisely.
  29 #
  30 # Notice option "include" won't be rewritten by command "CONFIG REWRITE"
  31 # from admin or Redis Sentinel. Since Redis always uses the last processed
  32 # line as value of a configuration directive, you'd better put includes
  33 # at the beginning of this file to avoid overwriting config change at runtime.
  34 #
  35 # If instead you are interested in using includes to override configuration
  36 # options, it is better to use include as the last line.
  37 #
  38 # 引入外部配置文件
  39 # include /path/to/local.conf
  40 # include /path/to/other.conf
  41 
  42 ################################## MODULES #####################################
  43 
  44 # Load modules at startup. If the server is not able to load modules
  45 # it will abort. It is possible to use multiple loadmodule directives.
  46 #
  47 # 引入第三方模块
  48 # loadmodule /path/to/my_module.so
  49 # loadmodule /path/to/other_module.so
  50 
  51 ################################## NETWORK #####################################
  52 
  53 # By default, if no "bind" configuration directive is specified, Redis listens
  54 # for connections from all the network interfaces available on the server.
  55 # It is possible to listen to just one or multiple selected interfaces using
  56 # the "bind" configuration directive, followed by one or more IP addresses.
  57 #
  58 # Examples:
  59 #
  60 # bind 192.168.1.100 10.0.0.1
  61 # bind 127.0.0.1 ::1
  62 #
  63 # ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the
  64 # internet, binding to all the interfaces is dangerous and will expose the
  65 # instance to everybody on the internet. So by default we uncomment the
  66 # following bind directive, that will force Redis to listen only into
  67 # the IPv4 lookback interface address (this means Redis will be able to
  68 # accept connections only from clients running into the same computer it
  69 # is running).
  70 #
  71 # IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
  72 # JUST COMMENT THE FOLLOWING LINE.
  73 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  74 # 绑定主机网卡地址
  75 bind 127.0.0.1
  76 
  77 # Protected mode is a layer of security protection, in order to avoid that
  78 # Redis instances left open on the internet are accessed and exploited.
  79 #
  80 # When protected mode is on and if:
  81 #
  82 # 1) The server is not binding explicitly to a set of addresses using the
  83 #    "bind" directive.
  84 # 2) No password is configured.
  85 #
  86 # The server only accepts connections from clients connecting from the
  87 # IPv4 and IPv6 loopback addresses 127.0.0.1 and ::1, and from Unix domain
  88 # sockets.
  89 #
  90 # By default protected mode is enabled. You should disable it only if
  91 # you are sure you want clients from other hosts to connect to Redis
  92 # even if no authentication is configured, nor a specific set of interfaces
  93 # are explicitly listed using the "bind" directive.
  94 # 保护模式
  95 protected-mode yes
  96 
  97 # Accept connections on the specified port, default is 6379 (IANA #815344).
  98 # If port 0 is specified Redis will not listen on a TCP socket.
  99 # 端口号
 100 # 如果设为0, redis将不在socket上监听任何客户端连接。
 101 port 6379
 102 
 103 # TCP listen() backlog.
 104 #
 105 # In high requests-per-second environments you need an high backlog in order
 106 # to avoid slow clients connections issues. Note that the Linux kernel
 107 # will silently truncate it to the value of /proc/sys/net/core/somaxconn so
 108 # make sure to raise both the value of somaxconn and tcp_max_syn_backlog
 109 # in order to get the desired effect.
 110 # TCP 监听的最大容纳数量
 111 # 此参数确定了TCP连接中已完成队列(完成三次握手之后)的长度,
 112 # 当系统并发量大并且客户端速度缓慢的时候,你需要把这个值调高以避免客户端连接缓慢的问题。
 113 # Linux 内核会一声不响的把这个值缩小成 /proc/sys/net/core/somaxconn 对应的值,默认是511,而Linux的默认参数值是128。
 114 # 所以可以将这二个参数一起参考设定,你以便达到你的预期。
 115 tcp-backlog 511
 116 
 117 # Unix socket.
 118 #
 119 # Specify the path for the Unix socket that will be used to listen for
 120 # incoming connections. There is no default, so Redis will not listen
 121 # on a unix socket when not specified.
 122 #
 123 # unixsocket /tmp/redis.sock
 124 # unixsocketperm 700
 125 
 126 # Close the connection after a client is idle for N seconds (0 to disable)
 127 # 客户端和Redis服务端的连接超时时间,默认是0,表示永不超时。
 128 timeout 0
 129 
 130 # TCP keepalive.
 131 #
 132 # If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence
 133 # of communication. This is useful for two reasons:
 134 #
 135 # 1) Detect dead peers.
 136 # 2) Take the connection alive from the point of view of network
 137 #    equipment in the middle.
 138 #
 139 # On Linux, the specified value (in seconds) is the period used to send ACKs.
 140 # Note that to close the connection the double of the time is needed.
 141 # On other kernels the period depends on the kernel configuration.
 142 #
 143 # A reasonable value for this option is 300 seconds, which is the new
 144 # Redis default starting with Redis 3.2.1.
 145 # tcp 心跳包
 146 # 如何设置为非零, 则在与客户端缺乏通信的时候使用 SO_KEEPALIVE 发送 TCP ACKs 到客户端。
 147 # 这配置之所以有用, 是因为以下两点:
 148 # 1)检测节点猝死
 149 # 2)保持网络设备与子节点之间连接
 150 # 推荐合理时间为300秒
 151 tcp-keepalive 300
 152 
 153 ################################# GENERAL #####################################
 154 
 155 # By default Redis does not run as a daemon. Use 'yes' if you need it.
 156 # Note that Redis will write a pid file in /var/run/redis.pid when daemonized.
 157 # 是否设置Redis为守护进程, 默认为no
 158 # 当Redis作为守护进程运行的时候,它会写一个 pid 到 /var/run/redis.pid 文件里面。
 159 daemonize no
 160 
 161 # If you run Redis from upstart or systemd, Redis can interact with your
 162 # supervision tree. Options:
 163 #   supervised no      - no supervision interaction
 164 #   supervised upstart - signal upstart by putting Redis into SIGSTOP mode
 165 #   supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET
 166 #   supervised auto    - detect upstart or systemd method based on
 167 #                        UPSTART_JOB or NOTIFY_SOCKET environment variables
 168 # Note: these supervision methods only signal "process is ready."
 169 #       They do not enable continuous liveness pings back to your supervisor.
 170 # 可以通过upstart和systemd运行Redis
 171 # supervised no 无监督交互
 172 # supervised upstart 通过upstart信号与Redis SIGSTOP模式交互
 173 # supervised systemd systemd信号向$NOTIFY_SOCKET中写入READY=1
 174 # supervised auto 基于upstart或systemd检测为UPSTART_JOB或NOTIFY_SOCKET的环境变量
 175 supervised no
 176 
 177 # If a pid file is specified, Redis writes it where specified at startup
 178 # and removes it at exit.
 179 #
 180 # When the server runs non daemonized, no pid file is created if none is
 181 # specified in the configuration. When the server is daemonized, the pid file
 182 # is used even if not specified, defaulting to "/var/run/redis.pid".
 183 #
 184 # Creating a pid file is best effort: if Redis is not able to create it
 185 # nothing bad happens, the server will start and run normally.
 186 # 当 Redis 以守护进程的方式运行的时候,Redis 默认会把 pid 文件放在/var/run/redis.pid
 187 # 可配置到其他地址,当运行多个 redis 服务时,需要指定不同的 pid 文件和端口
 188 # 指定存储Redis进程号的文件路径
 189 pidfile /var/run/redis_6379.pid
 190 
 191 # Specify the server verbosity level.
 192 # This can be one of:
 193 # debug (a lot of information, useful for development/testing)
 194 # verbose (many rarely useful info, but not a mess like the debug level)
 195 # notice (moderately verbose, what you want in production probably)
 196 # warning (only very important / critical messages are logged)
 197 # 日志级别
 198 # debug (使用与开发与测试阶段)
 199 # verbose (许多很少用到的info, 但是不像debug等级那么混乱)
 200 # notice (仅试用于生产)
 201 # warning (仅仅一些非常重要的信息被记录)
 202 loglevel notice
 203 
 204 # Specify the log file name. Also the empty string can be used to force
 205 # Redis to log on the standard output. Note that if you use standard
 206 # output for logging but daemonize, logs will be sent to /dev/null
 207 # 配置 log 文件地址,默认打印在命令行终端的窗口上,也可设为/dev/null屏蔽日志
 208 logfile ""
 209 
 210 # To enable logging to the system logger, just set 'syslog-enabled' to yes,
 211 # and optionally update the other syslog parameters to suit your needs.
 212 # 把日志记录到系统日志,就把它改成 yes,
 213 # 也可以可选择性的更新其他的syslog 参数以达到你的要求
 214 # syslog-enabled no
 215 
 216 # Specify the syslog identity.
 217 # 指定日志身份
 218 # syslog-ident redis
 219 
 220 # Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
 221 # 指定日志设备, 必须用户在local0-local7之间
 222 # syslog-facility local0
 223 
 224 # Set the number of databases. The default database is DB 0, you can select
 225 # a different one on a per-connection basis using SELECT <dbid> where
 226 # dbid is a number between 0 and 'databases'-1
 227 # 可用的数据库数,默认值为16,默认数据库为0,数据库范围在0-(database-1)之间
 228 databases 16
 229 
 230 # By default Redis shows an ASCII art logo only when started to log to the
 231 # standard output and if the standard output is a TTY. Basically this means
 232 # that normally a logo is displayed only in interactive sessions.
 233 #
 234 # However it is possible to force the pre-4.0 behavior and always show a
 235 # ASCII art logo in startup logs by setting the following option to yes.
 236 # 启用日志是否打印logo
 237 always-show-logo yes
 238 
 239 ################################ SNAPSHOTTING  ################################
 240 #
 241 # Save the DB on disk:
 242 #
 243 #   save <seconds> <changes>
 244 #
 245 #   Will save the DB if both the given number of seconds and the given
 246 #   number of write operations against the DB occurred.
 247 #
 248 #   In the example below the behaviour will be to save:
 249 #   after 900 sec (15 min) if at least 1 key changed
 250 #   after 300 sec (5 min) if at least 10 keys changed
 251 #   after 60 sec if at least 10000 keys changed
 252 #
 253 #   Note: you can disable saving completely by commenting out all "save" lines.
 254 #
 255 #   It is also possible to remove all the previously configured save
 256 #   points by adding a save directive with a single empty string argument
 257 #   like in the following example:
 258 #
 259 #   save ""
 260 # 指定在多长时间内,有多少次更新操作,就将数据同步到数据文件,可以多个条件配合
 261 
 262 # Redis默认配置文件中提供了三个条件:
 263 save 900 1
 264 save 300 10
 265 save 60 10000
 266 # 分别表示900秒(15分钟)内有1个更改,300秒(5分钟)内有10个更改以及60秒内有10000个更改。
 267 
 268 # By default Redis will stop accepting writes if RDB snapshots are enabled
 269 # (at least one save point) and the latest background save failed.
 270 # This will make the user aware (in a hard way) that data is not persisting
 271 # on disk properly, otherwise chances are that no one will notice and some
 272 # disaster will happen.
 273 #
 274 # If the background saving process will start working again Redis will
 275 # automatically allow writes again.
 276 #
 277 # However if you have setup your proper monitoring of the Redis server
 278 # and persistence, you may want to disable this feature so that Redis will
 279 # continue to work as usual even if there are problems with disk,
 280 # permissions, and so forth.
 281 # 默认情况下, 如果redis最后一次的后台保存失败, redis将停止接受写操作, 
 282 # 以一种强制的方式让用户知晓数据不能正确的持久化到磁盘, 否则就不会有人注意到灾难的发生。
 283 # 如果后台保存进程重新启动工作, redis将自动允许写操作。
 284 stop-writes-on-bgsave-error yes
 285 
 286 # Compress string objects using LZF when dump .rdb databases?
 287 # For default that's set to 'yes' as it's almost always a win.
 288 # If you want to save some CPU in the saving child set it to 'no' but
 289 # the dataset will likely be bigger if you have compressible values or keys.
 290 # 指定存储至本地数据库时是否压缩数据, 默认为yes, Redis采用LZF压缩, 如果为了节省CPU时间, 可以关闭该选项,
 291 # 但会导致数据库文件变的巨大。
 292 rdbcompression yes
 293 
 294 # Since version 5 of RDB a CRC64 checksum is placed at the end of the file.
 295 # This makes the format more resistant to corruption but there is a performance
 296 # hit to pay (around 10%) when saving and loading RDB files, so you can disable it
 297 # for maximum performances.
 298 #
 299 # RDB files created with checksum disabled have a checksum of zero that will
 300 # tell the loading code to skip the check.
 301 # 读取和写入的时候是否支持CRC64校验,默认是开启的。
 302 rdbchecksum yes
 303 
 304 # The filename where to dump the DB
 305 # 指定本地数据库文件名,默认值为dump.rdb
 306 dbfilename dump.rdb
 307 
 308 # The working directory.
 309 #
 310 # The DB will be written inside this directory, with the filename specified
 311 # above using the 'dbfilename' configuration directive.
 312 #
 313 # The Append Only File will also be created inside this directory.
 314 #
 315 # Note that you must specify a directory here, not a file name.
 316 # 指定本地数据库存放目录
 317 dir ./
 318 
 319 ################################# REPLICATION #################################
 320 
 321 # Master-Slave replication. Use slaveof to make a Redis instance a copy of
 322 # another Redis server. A few things to understand ASAP about Redis replication.
 323 #
 324 # 1) Redis replication is asynchronous, but you can configure a master to
 325 #    stop accepting writes if it appears to be not connected with at least
 326 #    a given number of slaves.
 327 # 2) Redis slaves are able to perform a partial resynchronization with the
 328 #    master if the replication link is lost for a relatively small amount of
 329 #    time. You may want to configure the replication backlog size (see the next
 330 #    sections of this file) with a sensible value depending on your needs.
 331 # 3) Replication is automatic and does not need user intervention. After a
 332 #    network partition slaves automatically try to reconnect to masters
 333 #    and resynchronize with them.
 334 #
 335 # 设置当本机为slav服务时, 设置master服务的IP地址及端口, 在Redis启动时, 它会自动从master进行数据同步。
 336 # slaveof <masterip> <masterport>
 337 
 338 # If the master is password protected (using the "requirepass" configuration
 339 # directive below) it is possible to tell the slave to authenticate before
 340 # starting the replication synchronization process, otherwise the master will
 341 # refuse the slave request.
 342 # 
 343 # 当master服务设置了密码保护时,slav服务连接master的密码
 344 # masterauth <master-password>
 345 
 346 # When a slave loses its connection with the master, or when the replication
 347 # is still in progress, the slave can act in two different ways:
 348 #
 349 # 1) if slave-serve-stale-data is set to 'yes' (the default) the slave will
 350 #    still reply to client requests, possibly with out of date data, or the
 351 #    data set may just be empty if this is the first synchronization.
 352 #
 353 # 2) if slave-serve-stale-data is set to 'no' the slave will reply with
 354 #    an error "SYNC with master in progress" to all the kind of commands
 355 #    but to INFO and SLAVEOF.
 356 #
 357 # 当slave服务器和master服务器失去连接后, 或者当数据正在复制传输的时候, 如果此参数值设置“yes”, 
 358 # slave服务器可以继续接受客户端的请求, 否则, 会返回给请求的客户端如下信息“SYNC with master in progress”,
 359 # 除了INFO,SLAVEOF这两个命令。
 360 slave-serve-stale-data yes
 361 
 362 # You can configure a slave instance to accept writes or not. Writing against
 363 # a slave instance may be useful to store some ephemeral data (because data
 364 # written on a slave will be easily deleted after resync with the master) but
 365 # may also cause problems if clients are writing to it because of a
 366 # misconfiguration.
 367 #
 368 # Since Redis 2.6 by default slaves are read-only.
 369 #
 370 # Note: read only slaves are not designed to be exposed to untrusted clients
 371 # on the internet. It's just a protection layer against misuse of the instance.
 372 # Still a read only slave exports by default all the administrative commands
 373 # such as CONFIG, DEBUG, and so forth. To a limited extent you can improve
 374 # security of read only slaves using 'rename-command' to shadow all the
 375 # administrative / dangerous commands.
 376 # 是否允许slave服务器节点只提供读服务。
 377 slave-read-only yes
 378 
 379 # Replication SYNC strategy: disk or socket.
 380 # 主从同步支持两种策略,即disk和socket方式
 381 #
 382 # -------------------------------------------------------
 383 # WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY
 384 # 警告: 目前无磁盘DISKLESS方式复制正在处于实验阶段
 385 # -------------------------------------------------------
 386 #
 387 # 新的slave端和重连的salve端不允许去继续同步进程,这被称之为“完全同步”。 
 388 # 一个RDB文件从master端传到slave端,分为两种情况: 
 389 # 1、支持disk:master端将RDB file写到disk,稍后再传送到slave端; 
 390 # 2、无磁盘diskless:master端直接将RDB file传到slave socket,不需要与disk进行交互。 
 391 # 无磁盘diskless方式适合磁盘读写速度慢但网络带宽非常高的环境。
 392 #
 393 # New slaves and reconnecting slaves that are not able to continue the replication
 394 # process just receiving differences, need to do what is called a "full
 395 # synchronization". An RDB file is transmitted from the master to the slaves.
 396 # The transmission can happen in two different ways:
 397 #
 398 # 1) Disk-backed: The Redis master creates a new process that writes the RDB
 399 #                 file on disk. Later the file is transferred by the parent
 400 #                 process to the slaves incrementally.
 401 # 2) Diskless: The Redis master creates a new process that directly writes the
 402 #              RDB file to slave sockets, without touching the disk at all.
 403 #
 404 # With disk-backed replication, while the RDB file is generated, more slaves
 405 # can be queued and served with the RDB file as soon as the current child producing
 406 # the RDB file finishes its work. With diskless replication instead once
 407 # the transfer starts, new slaves arriving will be queued and a new transfer
 408 # will start when the current one terminates.
 409 #
 410 # When diskless replication is used, the master waits a configurable amount of
 411 # time (in seconds) before starting the transfer in the hope that multiple slaves
 412 # will arrive and the transfer can be parallelized.
 413 #
 414 # With slow disks and fast (large bandwidth) networks, diskless replication
 415 # works better.
 416 
 417 # 默认不使用diskless同步方式 
 418 repl-diskless-sync no
 419 
 420 # When diskless replication is enabled, it is possible to configure the delay
 421 # the server waits in order to spawn the child that transfers the RDB via socket
 422 # to the slaves.
 423 #
 424 # This is important since once the transfer starts, it is not possible to serve
 425 # new slaves arriving, that will be queued for the next RDB transfer, so the server
 426 # waits a delay in order to let more slaves arrive.
 427 #
 428 # The delay is specified in seconds, and by default is 5 seconds. To disable
 429 # it entirely just set it to 0 seconds and the transfer will start ASAP.
 430 # 无磁盘diskless方式在进行数据传递之前会有一个时间的延迟,以便slave端能够进行到待传送的目标队列中,这个时间默认是5秒。
 431 repl-diskless-sync-delay 5
 432 
 433 # Slaves send PINGs to server in a predefined interval. It's possible to change
 434 # this interval with the repl_ping_slave_period option. The default value is 10
 435 # seconds.
 436 #
 437 # slave端向server端发送pings的时间区间设置,默认为10秒 
 438 # repl-ping-slave-period 10
 439 
 440 # The following option sets the replication timeout for:
 441 #
 442 # 1) Bulk transfer I/O during SYNC, from the point of view of slave.
 443 # 2) Master timeout from the point of view of slaves (data, pings).
 444 # 3) Slave timeout from the point of view of masters (REPLCONF ACK pings).
 445 #
 446 # It is important to make sure that this value is greater than the value
 447 # specified for repl-ping-slave-period otherwise a timeout will be detected
 448 # every time there is low traffic between the master and the slave.
 449 #
 450 # 设置主从复制超时时间, 默认60秒 
 451 # repl-timeout 60
 452 
 453 # Disable TCP_NODELAY on the slave socket after SYNC?
 454 #
 455 # If you select "yes" Redis will use a smaller number of TCP packets and
 456 # less bandwidth to send data to slaves. But this can add a delay for
 457 # the data to appear on the slave side, up to 40 milliseconds with
 458 # Linux kernels using a default configuration.
 459 #
 460 # If you select "no" the delay for data to appear on the slave side will
 461 # be reduced but more bandwidth will be used for replication.
 462 #
 463 # By default we optimize for low latency, but in very high traffic conditions
 464 # or when the master and slaves are many hops away, turning this to "yes" may
 465 # be a good idea.
 466 # 是否启用TCP_NODELAY,如果启用则会使用少量的TCP包和带宽去进行数据传输到slave端,
 467 # 当然速度会比较慢;如果不启用则传输速度比较快,但是会占用比较多的带宽。 
 468 repl-disable-tcp-nodelay no
 469 
 470 # Set the replication backlog size. The backlog is a buffer that accumulates
 471 # slave data when slaves are disconnected for some time, so that when a slave
 472 # wants to reconnect again, often a full resync is not needed, but a partial
 473 # resync is enough, just passing the portion of data the slave missed while
 474 # disconnected.
 475 #
 476 # The bigger the replication backlog, the longer the time the slave can be
 477 # disconnected and later be able to perform a partial resynchronization.
 478 #
 479 # The backlog is only allocated once there is at least a slave connected.
 480 #
 481 # 设置backlog的大小,backlog是一个缓冲区,在slave端失连时存放要同步到slave的数据,因此当一个slave要重连时,
 482 # 经常是不需要完全同步的,执行局部同步就足够了。backlog设置的越大,slave可以失连的时间就越长。 
 483 # repl-backlog-size 1mb
 484 
 485 # After a master has no longer connected slaves for some time, the backlog
 486 # will be freed. The following option configures the amount of seconds that
 487 # need to elapse, starting from the time the last slave disconnected, for
 488 # the backlog buffer to be freed.
 489 #
 490 # Note that slaves never free the backlog for timeout, since they may be
 491 # promoted to masters later, and should be able to correctly "partially
 492 # resynchronize" with the slaves: hence they should always accumulate backlog.
 493 #
 494 # A value of 0 means to never release the backlog.
 495 #
 496 # 如果一段时间后没有slave连接到master,则backlog size的内存将会被释放。如果值为0则表示永远不释放这部份内存。 
 497 # repl-backlog-ttl 3600
 498 
 499 # The slave priority is an integer number published by Redis in the INFO output.
 500 # It is used by Redis Sentinel in order to select a slave to promote into a
 501 # master if the master is no longer working correctly.
 502 #
 503 # A slave with a low priority number is considered better for promotion, so
 504 # for instance if there are three slaves with priority 10, 100, 25 Sentinel will
 505 # pick the one with priority 10, that is the lowest.
 506 #
 507 # However a special priority of 0 marks the slave as not able to perform the
 508 # role of master, so a slave with priority of 0 will never be selected by
 509 # Redis Sentinel for promotion.
 510 #
 511 # By default the priority is 100.
 512 # 指定slave的优先级。在不只1个slave存在的部署环境下,当master宕机时,Redis
 513 # Sentinel会将priority值最小的slave提升为master。
 514 # 这个值越小,就越会被优先选中,需要注意的是,
 515 # 若该配置项为0,则对应的slave永远不会自动提升为master。 
 516 slave-priority 100
 517 
 518 # It is possible for a master to stop accepting writes if there are less than
 519 # N slaves connected, having a lag less or equal than M seconds.
 520 #
 521 # The N slaves need to be in "online" state.
 522 #
 523 # The lag in seconds, that must be <= the specified value, is calculated from
 524 # the last ping received from the slave, that is usually sent every second.
 525 #
 526 # This option does not GUARANTEE that N replicas will accept the write, but
 527 # will limit the window of exposure for lost writes in case not enough slaves
 528 # are available, to the specified number of seconds.
 529 #
 530 # For example to require at least 3 slaves with a lag <= 10 seconds use:
 531 #
 532 # 设置当一个master端的可用slave少于3个,延迟时间大于10秒时,不接收写操作。
 533 # min-slaves-to-write 3
 534 # min-slaves-max-lag 10
 535 #
 536 # Setting one or the other to 0 disables the feature.
 537 #
 538 # By default min-slaves-to-write is set to 0 (feature disabled) and
 539 # min-slaves-max-lag is set to 10.
 540 
 541 # A Redis master is able to list the address and port of the attached
 542 # slaves in different ways. For example the "INFO replication" section
 543 # offers this information, which is used, among other tools, by
 544 # Redis Sentinel in order to discover slave instances.
 545 # Another place where this info is available is in the output of the
 546 # "ROLE" command of a master.
 547 #
 548 # The listed IP and address normally reported by a slave is obtained
 549 # in the following way:
 550 #
 551 #   IP: The address is auto detected by checking the peer address
 552 #   of the socket used by the slave to connect with the master.
 553 #
 554 #   Port: The port is communicated by the slave during the replication
 555 #   handshake, and is normally the port that the slave is using to
 556 #   list for connections.
 557 #
 558 # However when port forwarding or Network Address Translation (NAT) is
 559 # used, the slave may be actually reachable via different IP and port
 560 # pairs. The following two options can be used by a slave in order to
 561 # report to its master a specific set of IP and port, so that both INFO
 562 # and ROLE will report those values.
 563 #
 564 # There is no need to use both the options if you need to override just
 565 # the port or the IP address.
 566 # 
 567 # slave-announce-ip 5.5.5.5
 568 # slave-announce-port 1234
 569 
 570 ################################## SECURITY ###################################
 571 
 572 # Require clients to issue AUTH <PASSWORD> before processing any other
 573 # commands.  This might be useful in environments in which you do not trust
 574 # others with access to the host running redis-server.
 575 #
 576 # This should stay commented out for backward compatibility and because most
 577 # people do not need auth (e.g. they run their own servers).
 578 #
 579 # Warning: since Redis is pretty fast an outside user can try up to
 580 # 150k passwords per second against a good box. This means that you should
 581 # use a very strong password otherwise it will be very easy to break.
 582 #
 583 # 设置连接redis的密码
 584 # redis速度相当快,一个外部用户在一秒钟进行150K次密码尝试,需指定强大的密码来防止暴力破解
 585 # requirepass foobared
 586 
 587 # Command renaming.
 588 #
 589 # It is possible to change the name of dangerous commands in a shared
 590 # environment. For instance the CONFIG command may be renamed into something
 591 # hard to guess so that it will still be available for internal-use tools
 592 # but not available for general clients.
 593 #
 594 # Example:
 595 #
 596 # rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
 597 #
 598 # It is also possible to completely kill a command by renaming it into
 599 # an empty string:
 600 #
 601 # 重命名一些高危命令,用来禁止高危命令
 602 # rename-command CONFIG ""
 603 #
 604 # Please note that changing the name of commands that are logged into the
 605 # AOF file or transmitted to slaves may cause problems.
 606 
 607 ################################### CLIENTS ####################################
 608 
 609 # Set the max number of connected clients at the same time. By default
 610 # this limit is set to 10000 clients, however if the Redis server is not
 611 # able to configure the process file limit to allow for the specified limit
 612 # the max number of allowed clients is set to the current file limit
 613 # minus 32 (as Redis reserves a few file descriptors for internal uses).
 614 #
 615 # Once the limit is reached Redis will close all the new connections sending
 616 # an error 'max number of clients reached'.
 617 #
 618 # 限制同时连接的客户数量,默认是10000
 619 # 当连接数超过这个值时,redis 将不再接收其他连接请求,客户端尝试连接时将收到 error 信息
 620 # maxclients 10000
 621 
 622 ############################## MEMORY MANAGEMENT ################################
 623 
 624 # Set a memory usage limit to the specified amount of bytes.
 625 # When the memory limit is reached Redis will try to remove keys
 626 # according to the eviction policy selected (see maxmemory-policy).
 627 #
 628 # If Redis can't remove keys according to the policy, or if the policy is
 629 # set to 'noeviction', Redis will start to reply with errors to commands
 630 # that would use more memory, like SET, LPUSH, and so on, and will continue
 631 # to reply to read-only commands like GET.
 632 #
 633 # This option is usually useful when using Redis as an LRU or LFU cache, or to
 634 # set a hard memory limit for an instance (using the 'noeviction' policy).
 635 #
 636 # WARNING: If you have slaves attached to an instance with maxmemory on,
 637 # the size of the output buffers needed to feed the slaves are subtracted
 638 # from the used memory count, so that network problems / resyncs will
 639 # not trigger a loop where keys are evicted, and in turn the output
 640 # buffer of slaves is full with DELs of keys evicted triggering the deletion
 641 # of more keys, and so forth until the database is completely emptied.
 642 #
 643 # In short... if you have slaves attached it is suggested that you set a lower
 644 # limit for maxmemory so that there is some free RAM on the system for slave
 645 # output buffers (but this is not needed if the policy is 'noeviction').
 646 #
 647 # 设置redis能够使用的最大内存。
 648 # 达到最大内存设置后,Redis会先尝试清除已到期或即将到期的Key(设置过expire信息的key)
 649 # 在删除时,按照过期时间进行删除,最早将要被过期的key将最先被删除
 650 # 如果已到期或即将到期的key删光,仍进行set操作,那么将返回错误
 651 # 此时redis将不再接收写请求,只接收get请求。
 652 # maxmemory的设置比较适合于把redis当作于类似memcached的缓存来使用
 653 # maxmemory <bytes>
 654 
 655 # MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
 656 # is reached. You can select among five behaviors:
 657 #
 658 # volatile-lru -> Evict using approximated LRU among the keys with an expire set.
 659 # allkeys-lru -> Evict any key using approximated LRU.
 660 # volatile-lfu -> Evict using approximated LFU among the keys with an expire set.
 661 # allkeys-lfu -> Evict any key using approximated LFU.
 662 # volatile-random -> Remove a random key among the ones with an expire set.
 663 # allkeys-random -> Remove a random key, any key.
 664 # volatile-ttl -> Remove the key with the nearest expire time (minor TTL)
 665 # noeviction -> Don't evict anything, just return an error on write operations.
 666 #
 667 # LRU means Least Recently Used
 668 # LFU means Least Frequently Used
 669 #
 670 # Both LRU, LFU and volatile-ttl are implemented using approximated
 671 # randomized algorithms.
 672 #
 673 # Note: with any of the above policies, Redis will return an error on write
 674 #       operations, when there are no suitable keys for eviction.
 675 #
 676 #       At the date of writing these commands are: set setnx setex append
 677 #       incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd
 678 #       sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby
 679 #       zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby
 680 #       getset mset msetnx exec sort
 681 #
 682 # The default is:
 683 #
 684 # 最大内存清理缓存策略
 685 # 六种缓存清除策略:
 686 # 1) volatile-lru:使用LRU算法移除key,只针对设置了过期时间的键
 687 # 2) allkeys-lru:使用LRU算法移除
 688 # 3) volatile-random:在过期集合中移除随机的key,只针对设置了过期时间的键
 689 # 4) allkeys-random:移除随机的键
 690 # 5) volatile-ttl:移除那些TTL值小的key,即那些最近要过期的键
 691 # 6) noeviction:不进行移除。针对写操作,只是返回错误信息。永不过期策略。(默认)
 692 #
 693 # maxmemory-policy noeviction
 694 
 695 # LRU, LFU and minimal TTL algorithms are not precise algorithms but approximated
 696 # algorithms (in order to save memory), so you can tune it for speed or
 697 # accuracy. For default Redis will check five keys and pick the one that was
 698 # used less recently, you can change the sample size using the following
 699 # configuration directive.
 700 #
 701 # The default of 5 produces good enough results. 10 Approximates very closely
 702 # true LRU but costs more CPU. 3 is faster but not very accurate.
 703 #
 704 # LRU算法检查的keys个数
 705 # maxmemory-samples 5
 706 
 707 ############################# LAZY FREEING ####################################
 708 
 709 # Redis has two primitives to delete keys. One is called DEL and is a blocking
 710 # deletion of the object. It means that the server stops processing new commands
 711 # in order to reclaim all the memory associated with an object in a synchronous
 712 # way. If the key deleted is associated with a small object, the time needed
 713 # in order to execute the DEL command is very small and comparable to most other
 714 # O(1) or O(log_N) commands in Redis. However if the key is associated with an
 715 # aggregated value containing millions of elements, the server can block for
 716 # a long time (even seconds) in order to complete the operation.
 717 #
 718 # For the above reasons Redis also offers non blocking deletion primitives
 719 # such as UNLINK (non blocking DEL) and the ASYNC option of FLUSHALL and
 720 # FLUSHDB commands, in order to reclaim memory in background. Those commands
 721 # are executed in constant time. Another thread will incrementally free the
 722 # object in the background as fast as possible.
 723 #
 724 # DEL, UNLINK and ASYNC option of FLUSHALL and FLUSHDB are user-controlled.
 725 # It's up to the design of the application to understand when it is a good
 726 # idea to use one or the other. However the Redis server sometimes has to
 727 # delete keys or flush the whole database as a side effect of other operations.
 728 # Specifically Redis deletes objects independently of a user call in the
 729 # following scenarios:
 730 #
 731 # 1) On eviction, because of the maxmemory and maxmemory policy configurations,
 732 #    in order to make room for new data, without going over the specified
 733 #    memory limit.
 734 # 2) Because of expire: when a key with an associated time to live (see the
 735 #    EXPIRE command) must be deleted from memory.
 736 # 3) Because of a side effect of a command that stores data on a key that may
 737 #    already exist. For example the RENAME command may delete the old key
 738 #    content when it is replaced with another one. Similarly SUNIONSTORE
 739 #    or SORT with STORE option may delete existing keys. The SET command
 740 #    itself removes any old content of the specified key in order to replace
 741 #    it with the specified string.
 742 # 4) During replication, when a slave performs a full resynchronization with
 743 #    its master, the content of the whole database is removed in order to
 744 #    load the RDB file just transfered.
 745 #
 746 # In all the above cases the default is to delete objects in a blocking way,
 747 # like if DEL was called. However you can configure each case specifically
 748 # in order to instead release memory in a non-blocking way like if UNLINK
 749 # was called, using the following configuration directives:
 750 
 751 lazyfree-lazy-eviction no
 752 lazyfree-lazy-expire no
 753 lazyfree-lazy-server-del no
 754 slave-lazy-flush no
 755 
 756 ############################## APPEND ONLY MODE ###############################
 757 
 758 # By default Redis asynchronously dumps the dataset on disk. This mode is
 759 # good enough in many applications, but an issue with the Redis process or
 760 # a power outage may result into a few minutes of writes lost (depending on
 761 # the configured save points).
 762 #
 763 # The Append Only File is an alternative persistence mode that provides
 764 # much better durability. For instance using the default data fsync policy
 765 # (see later in the config file) Redis can lose just one second of writes in a
 766 # dramatic event like a server power outage, or a single write if something
 767 # wrong with the Redis process itself happens, but the operating system is
 768 # still running correctly.
 769 #
 770 # AOF and RDB persistence can be enabled at the same time without problems.
 771 # If the AOF is enabled on startup Redis will load the AOF, that is the file
 772 # with the better durability guarantees.
 773 #
 774 # Please check http://redis.io/topics/persistence for more information.
 775 
 776 # redis 默认每次更新操作后会在后台异步的把数据库镜像备份到磁盘,但该备份非常耗时,且备份不宜太频繁。
 777 # redis 同步数据文件是按上面save条件来同步的
 778 # 如果发生诸如拉闸限电、拔插头等状况,那么将造成比较大范围的数据丢失
 779 # 所以redis提供了另外一种更加高效的数据库备份及灾难恢复方式
 780 # 开启append only 模式后,redis 将每一次写操作请求都追加到appendonly.aof 文件中
 781 # redis重新启动时,会从该文件恢复出之前的状态。
 782 # 但可能会造成 appendonly.aof 文件过大,所以redis支持BGREWRITEAOF 指令,对appendonly.aof重新整理,默认是不开启的。 
 783 appendonly no
 784 
 785 # The name of the append only file (default: "appendonly.aof")
 786 
 787 # appendfilename aof备份文件名称, 默认为appendonly.aof
 788 appendfilename "appendonly.aof"
 789 
 790 # The fsync() call tells the Operating System to actually write data on disk
 791 # instead of waiting for more data in the output buffer. Some OS will really flush
 792 # data on disk, some other OS will just try to do it ASAP.
 793 #
 794 # Redis supports three different modes:
 795 #
 796 # no: don't fsync, just let the OS flush the data when it wants. Faster.
 797 # always: fsync after every write to the append only log. Slow, Safest.
 798 # everysec: fsync only one time every second. Compromise.
 799 #
 800 # The default is "everysec", as that's usually the right compromise between
 801 # speed and data safety. It's up to you to understand if you can relax this to
 802 # "no" that will let the operating system flush the output buffer when
 803 # it wants, for better performances (but if you can live with the idea of
 804 # some data loss consider the default persistence mode that's snapshotting),
 805 # or on the contrary, use "always" that's very slow but a bit safer than
 806 # everysec.
 807 #
 808 # More details please check the following article:
 809 # http://antirez.com/post/redis-persistence-demystified.html
 810 #
 811 # If unsure, use "everysec".
 812 
 813 # 设置对 appendonly.aof 文件进行同步的频率,有三种选择always、everysec、no,默认是everysec。
 814 # always: 同步操作, 表示每次写入操作都进行同步。性能较差但数据完整性比较好。
 815 # everysec: 异步操作, 每秒记录。如果一秒内宕机,有数据丢失。
 816 # no: 从不同步
 817 # appendfsync always
 818 appendfsync everysec
 819 # appendfsync no
 820 
 821 # 相同数据集的数据而言aof文件要远大于rdb文件,恢复速度慢于rdb。
 822 # aof运行效率要慢于rdb,每秒同步策略效率较好,不同步效率和rdb相同
 823 
 824 
 825 # When the AOF fsync policy is set to always or everysec, and a background
 826 # saving process (a background save or AOF log background rewriting) is
 827 # performing a lot of I/O against the disk, in some Linux configurations
 828 # Redis may block too long on the fsync() call. Note that there is no fix for
 829 # this currently, as even performing fsync in a different thread will block
 830 # our synchronous write(2) call.
 831 #
 832 # In order to mitigate this problem it's possible to use the following option
 833 # that will prevent fsync() from being called in the main process while a
 834 # BGSAVE or BGREWRITEAOF is in progress.
 835 #
 836 # This means that while another child is saving, the durability of Redis is
 837 # the same as "appendfsync none". In practical terms, this means that it is
 838 # possible to lose up to 30 seconds of log in the worst scenario (with the
 839 # default Linux settings).
 840 #
 841 # If you have latency problems turn this to "yes". Otherwise leave it as
 842 # "no" that is the safest pick from the point of view of durability.
 843 
 844 # 指定是否在后台aof文件rewrite期间调用fsync, 默认为no, 表示要调用fsync
 845 # (无论后台是否有子进程在刷盘)。Redis在后台写RDB文件或重写afo文件期间会存在大量磁盘IO,
 846 # 此时, 在某些linux系统中, 调用fsync可能会阻塞。
 847 no-appendfsync-on-rewrite no
 848 
 849 # Automatic rewrite of the append only file.
 850 # Redis is able to automatically rewrite the log file implicitly calling
 851 # BGREWRITEAOF when the AOF log size grows by the specified percentage.
 852 #
 853 # This is how it works: Redis remembers the size of the AOF file after the
 854 # latest rewrite (if no rewrite has happened since the restart, the size of
 855 # the AOF at startup is used).
 856 #
 857 # This base size is compared to the current size. If the current size is
 858 # bigger than the specified percentage, the rewrite is triggered. Also
 859 # you need to specify a minimal size for the AOF file to be rewritten, this
 860 # is useful to avoid rewriting the AOF file even if the percentage increase
 861 # is reached but it is still pretty small.
 862 #
 863 # Specify a percentage of zero in order to disable the automatic AOF
 864 # rewrite feature.
 865 
 866 # 指定Redis重写aof文件的条件, 默认为100, 表示与上次rewrite的aof文件大小相比,
 867 # 当前aof文件增长量超过上次afo文件大小的100%时, 就会触发background rewrite。
 868 # 若配置为0, 则会禁用自动rewrite。
 869 auto-aof-rewrite-percentage 100
 870 # Redis会记录上次重写时的AOF大小, 默认配置是当AOF文件大小是上次rewrite后大小的一倍且文件大于64M时触发。
 871 auto-aof-rewrite-min-size 64mb
 872 
 873 # AOF采用文件追加方式, 文件会越来越大为避免出现此种情况, 新增了重写机制,
 874 # 当AOF文件的大小超过所设定的阈值时, Redis就会启动AOF文件的内容压缩, 
 875 # 只保留可以恢复数据的最小指令集, 可以使用命令bgrewriteaof。
 876 
 877 # AOF文件持续增长而过大时, 会fork出一条新进程来将文件重写(也是先写临时文件最后再rename),
 878 # 遍历新进程的内存中数据, 每条记录有一条的Set语句。重写aof文件的操作, 并没有读取旧的aof文件, 
 879 # 而是将整个内存中的数据库内容用命令的方式重写了一个新的aof文件, 这点和快照有点类似。
 880 
 881 # An AOF file may be found to be truncated at the end during the Redis
 882 # startup process, when the AOF data gets loaded back into memory.
 883 # This may happen when the system where Redis is running
 884 # crashes, especially when an ext4 filesystem is mounted without the
 885 # data=ordered option (however this can't happen when Redis itself
 886 # crashes or aborts but the operating system still works correctly).
 887 #
 888 # Redis can either exit with an error when this happens, or load as much
 889 # data as possible (the default now) and start if the AOF file is found
 890 # to be truncated at the end. The following option controls this behavior.
 891 #
 892 # If aof-load-truncated is set to yes, a truncated AOF file is loaded and
 893 # the Redis server starts emitting a log to inform the user of the event.
 894 # Otherwise if the option is set to no, the server aborts with an error
 895 # and refuses to start. When the option is set to no, the user requires
 896 # to fix the AOF file using the "redis-check-aof" utility before to restart
 897 # the server.
 898 #
 899 # Note that if the AOF file will be found to be corrupted in the middle
 900 # the server will still exit with an error. This option only applies when
 901 # Redis will try to read more data from the AOF file but not enough bytes
 902 # will be found.
 903 # 是否加载不完整的aof文件来进行启动
 904 aof-load-truncated yes
 905 
 906 # When rewriting the AOF file, Redis is able to use an RDB preamble in the
 907 # AOF file for faster rewrites and recoveries. When this option is turned
 908 # on the rewritten AOF file is composed of two different stanzas:
 909 #
 910 #   [RDB file][AOF tail]
 911 #
 912 # When loading Redis recognizes that the AOF file starts with the "REDIS"
 913 # string and loads the prefixed RDB file, and continues loading the AOF
 914 # tail.
 915 #
 916 # This is currently turned off by default in order to avoid the surprise
 917 # of a format change, but will at some point be used as the default.
 918 aof-use-rdb-preamble no
 919 
 920 ################################ LUA SCRIPTING  ###############################
 921 
 922 # Max execution time of a Lua script in milliseconds.
 923 #
 924 # If the maximum execution time is reached Redis will log that a script is
 925 # still in execution after the maximum allowed time and will start to
 926 # reply to queries with an error.
 927 #
 928 # When a long running script exceeds the maximum execution time only the
 929 # SCRIPT KILL and SHUTDOWN NOSAVE commands are available. The first can be
 930 # used to stop a script that did not yet called write commands. The second
 931 # is the only way to shut down the server in the case a write command was
 932 # already issued by the script but the user doesn't want to wait for the natural
 933 # termination of the script.
 934 #
 935 # Set it to 0 or a negative value for unlimited execution without warnings.
 936 # 一个Lua脚本最长的执行时间,单位为毫秒,如果为0或负数表示无限执行时间,默认为5000
 937 lua-time-limit 5000
 938 
 939 ################################ REDIS CLUSTER  ###############################
 940 #
 941 # ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 942 # WARNING EXPERIMENTAL: Redis Cluster is considered to be stable code, however
 943 # in order to mark it as "mature" we need to wait for a non trivial percentage
 944 # of users to deploy it in production.
 945 # ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 946 #
 947 # Normal Redis instances can't be part of a Redis Cluster; only nodes that are
 948 # started as cluster nodes can. In order to start a Redis instance as a
 949 # cluster node enable the cluster support uncommenting the following:
 950 #
 951 # 一个正常的redis实例是不能做为一个redis集群的节点的, 除非它是以一个集群节点的方式进行启动。
 952 # 配置redis做为一个集群节点来启动
 953 # cluster-enabled yes
 954 
 955 # Every cluster node has a cluster configuration file. This file is not
 956 # intended to be edited by hand. It is created and updated by Redis nodes.
 957 # Every Redis Cluster node requires a different cluster configuration file.
 958 # Make sure that instances running in the same system do not have
 959 # overlapping cluster configuration file names.
 960 #
 961 # 每个集群节点都有一个集群配置文件, 这个文件不需要编辑, 它由redis节点来创建和更新。
 962 # 每个redis节点的集群配置文件不可以相同。 
 963 # cluster-config-file nodes-6379.conf
 964 
 965 # Cluster node timeout is the amount of milliseconds a node must be unreachable
 966 # for it to be considered in failure state.
 967 # Most other internal time limits are multiple of the node timeout.
 968 #
 969 # 设置集群节点超时时间, 如果超过了指定的超时时间后仍不可达, 则节点被认为是失败状态, 单位为毫秒。
 970 # cluster-node-timeout 15000
 971 
 972 # A slave of a failing master will avoid to start a failover if its data
 973 # looks too old.
 974 #
 975 # There is no simple way for a slave to actually have an exact measure of
 976 # its "data age", so the following two checks are performed:
 977 #
 978 # 1) If there are multiple slaves able to failover, they exchange messages
 979 #    in order to try to give an advantage to the slave with the best
 980 #    replication offset (more data from the master processed).
 981 #    Slaves will try to get their rank by offset, and apply to the start
 982 #    of the failover a delay proportional to their rank.
 983 #
 984 # 2) Every single slave computes the time of the last interaction with
 985 #    its master. This can be the last ping or command received (if the master
 986 #    is still in the "connected" state), or the time that elapsed since the
 987 #    disconnection with the master (if the replication link is currently down).
 988 #    If the last interaction is too old, the slave will not try to failover
 989 #    at all.
 990 #
 991 # The point "2" can be tuned by user. Specifically a slave will not perform
 992 # the failover if, since the last interaction with the master, the time
 993 # elapsed is greater than:
 994 #
 995 #   (node-timeout * slave-validity-factor) + repl-ping-slave-period
 996 #
 997 # So for example if node-timeout is 30 seconds, and the slave-validity-factor
 998 # is 10, and assuming a default repl-ping-slave-period of 10 seconds, the
 999 # slave will not try to failover if it was not able to talk with the master
1000 # for longer than 310 seconds.
1001 #
1002 # A large slave-validity-factor may allow slaves with too old data to failover
1003 # a master, while a too small value may prevent the cluster from being able to
1004 # elect a slave at all.
1005 #
1006 # For maximum availability, it is possible to set the slave-validity-factor
1007 # to a value of 0, which means, that slaves will always try to failover the
1008 # master regardless of the last time they interacted with the master.
1009 # (However they'll always try to apply a delay proportional to their
1010 # offset rank).
1011 #
1012 # Zero is the only value able to guarantee that when all the partitions heal
1013 # the cluster will always be able to continue.
1014 #
1015 # cluster-slave-validity-factor 10
1016 
1017 # Cluster slaves are able to migrate to orphaned masters, that are masters
1018 # that are left without working slaves. This improves the cluster ability
1019 # to resist to failures as otherwise an orphaned master can't be failed over
1020 # in case of failure if it has no working slaves.
1021 #
1022 # Slaves migrate to orphaned masters only if there are still at least a
1023 # given number of other working slaves for their old master. This number
1024 # is the "migration barrier". A migration barrier of 1 means that a slave
1025 # will migrate only if there is at least 1 other working slave for its master
1026 # and so forth. It usually reflects the number of slaves you want for every
1027 # master in your cluster.
1028 #
1029 # Default is 1 (slaves migrate only if their masters remain with at least
1030 # one slave). To disable migration just set it to a very large value.
1031 # A value of 0 can be set but is useful only for debugging and dangerous
1032 # in production.
1033 #
1034 # cluster-migration-barrier 1
1035 
1036 # By default Redis Cluster nodes stop accepting queries if they detect there
1037 # is at least an hash slot uncovered (no available node is serving it).
1038 # This way if the cluster is partially down (for example a range of hash slots
1039 # are no longer covered) all the cluster becomes, eventually, unavailable.
1040 # It automatically returns available as soon as all the slots are covered again.
1041 #
1042 # However sometimes you want the subset of the cluster which is working,
1043 # to continue to accept queries for the part of the key space that is still
1044 # covered. In order to do so, just set the cluster-require-full-coverage
1045 # option to no.
1046 #
1047 # cluster-require-full-coverage yes
1048 
1049 # In order to setup your cluster make sure to read the documentation
1050 # available at http://redis.io web site.
1051 
1052 ########################## CLUSTER DOCKER/NAT support  ########################
1053 
1054 # In certain deployments, Redis Cluster nodes address discovery fails, because
1055 # addresses are NAT-ted or because ports are forwarded (the typical case is
1056 # Docker and other containers).
1057 #
1058 # In order to make Redis Cluster working in such environments, a static
1059 # configuration where each node knows its public address is needed. The
1060 # following two options are used for this scope, and are:
1061 #
1062 # * cluster-announce-ip
1063 # * cluster-announce-port
1064 # * cluster-announce-bus-port
1065 #
1066 # Each instruct the node about its address, client port, and cluster message
1067 # bus port. The information is then published in the header of the bus packets
1068 # so that other nodes will be able to correctly map the address of the node
1069 # publishing the information.
1070 #
1071 # If the above options are not used, the normal Redis Cluster auto-detection
1072 # will be used instead.
1073 #
1074 # Note that when remapped, the bus port may not be at the fixed offset of
1075 # clients port + 10000, so you can specify any port and bus-port depending
1076 # on how they get remapped. If the bus-port is not set, a fixed offset of
1077 # 10000 will be used as usually.
1078 #
1079 # Example:
1080 #
1081 # cluster-announce-ip 10.1.1.5
1082 # cluster-announce-port 6379
1083 # cluster-announce-bus-port 6380
1084 
1085 ################################## SLOW LOG ###################################
1086 
1087 # The Redis Slow Log is a system to log queries that exceeded a specified
1088 # execution time. The execution time does not include the I/O operations
1089 # like talking with the client, sending the reply and so forth,
1090 # but just the time needed to actually execute the command (this is the only
1091 # stage of command execution where the thread is blocked and can not serve
1092 # other requests in the meantime).
1093 #
1094 # You can configure the slow log with two parameters: one tells Redis
1095 # what is the execution time, in microseconds, to exceed in order for the
1096 # command to get logged, and the other parameter is the length of the
1097 # slow log. When a new command is logged the oldest one is removed from the
1098 # queue of logged commands.
1099 
1100 # The following time is expressed in microseconds, so 1000000 is equivalent
1101 # to one second. Note that a negative number disables the slow log, while
1102 # a value of zero forces the logging of every command.
1103 slowlog-log-slower-than 10000
1104 
1105 # There is no limit to this length. Just be aware that it will consume memory.
1106 # You can reclaim memory used by the slow log with SLOWLOG RESET.
1107 slowlog-max-len 128
1108 
1109 ################################ LATENCY MONITOR ##############################
1110 
1111 # The Redis latency monitoring subsystem samples different operations
1112 # at runtime in order to collect data related to possible sources of
1113 # latency of a Redis instance.
1114 #
1115 # Via the LATENCY command this information is available to the user that can
1116 # print graphs and obtain reports.
1117 #
1118 # The system only logs operations that were performed in a time equal or
1119 # greater than the amount of milliseconds specified via the
1120 # latency-monitor-threshold configuration directive. When its value is set
1121 # to zero, the latency monitor is turned off.
1122 #
1123 # By default latency monitoring is disabled since it is mostly not needed
1124 # if you don't have latency issues, and collecting data has a performance
1125 # impact, that while very small, can be measured under big load. Latency
1126 # monitoring can easily be enabled at runtime using the command
1127 # "CONFIG SET latency-monitor-threshold <milliseconds>" if needed.
1128 latency-monitor-threshold 0
1129 
1130 ############################# EVENT NOTIFICATION ##############################
1131 
1132 # Redis can notify Pub/Sub clients about events happening in the key space.
1133 # This feature is documented at http://redis.io/topics/notifications
1134 #
1135 # For instance if keyspace events notification is enabled, and a client
1136 # performs a DEL operation on key "foo" stored in the Database 0, two
1137 # messages will be published via Pub/Sub:
1138 #
1139 # PUBLISH __keyspace@0__:foo del
1140 # PUBLISH __keyevent@0__:del foo
1141 #
1142 # It is possible to select the events that Redis will notify among a set
1143 # of classes. Every class is identified by a single character:
1144 #
1145 #  K     Keyspace events, published with __keyspace@<db>__ prefix.
1146 #  E     Keyevent events, published with __keyevent@<db>__ prefix.
1147 #  g     Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ...
1148 #  $     String commands
1149 #  l     List commands
1150 #  s     Set commands
1151 #  h     Hash commands
1152 #  z     Sorted set commands
1153 #  x     Expired events (events generated every time a key expires)
1154 #  e     Evicted events (events generated when a key is evicted for maxmemory)
1155 #  A     Alias for g$lshzxe, so that the "AKE" string means all the events.
1156 #
1157 #  The "notify-keyspace-events" takes as argument a string that is composed
1158 #  of zero or multiple characters. The empty string means that notifications
1159 #  are disabled.
1160 #
1161 #  Example: to enable list and generic events, from the point of view of the
1162 #           event name, use:
1163 #
1164 #  notify-keyspace-events Elg
1165 #
1166 #  Example 2: to get the stream of the expired keys subscribing to channel
1167 #             name __keyevent@0__:expired use:
1168 #
1169 #  notify-keyspace-events Ex
1170 #
1171 #  By default all notifications are disabled because most users don't need
1172 #  this feature and the feature has some overhead. Note that if you don't
1173 #  specify at least one of K or E, no events will be delivered.
1174 notify-keyspace-events ""
1175 
1176 ############################### ADVANCED CONFIG ###############################
1177 
1178 # Hashes are encoded using a memory efficient data structure when they have a
1179 # small number of entries, and the biggest entry does not exceed a given
1180 # threshold. These thresholds can be configured using the following directives.
1181 hash-max-ziplist-entries 512
1182 hash-max-ziplist-value 64
1183 
1184 # Lists are also encoded in a special way to save a lot of space.
1185 # The number of entries allowed per internal list node can be specified
1186 # as a fixed maximum size or a maximum number of elements.
1187 # For a fixed maximum size, use -5 through -1, meaning:
1188 # -5: max size: 64 Kb  <-- not recommended for normal workloads
1189 # -4: max size: 32 Kb  <-- not recommended
1190 # -3: max size: 16 Kb  <-- probably not recommended
1191 # -2: max size: 8 Kb   <-- good
1192 # -1: max size: 4 Kb   <-- good
1193 # Positive numbers mean store up to _exactly_ that number of elements
1194 # per list node.
1195 # The highest performing option is usually -2 (8 Kb size) or -1 (4 Kb size),
1196 # but if your use case is unique, adjust the settings as necessary.
1197 list-max-ziplist-size -2
1198 
1199 # Lists may also be compressed.
1200 # Compress depth is the number of quicklist ziplist nodes from *each* side of
1201 # the list to *exclude* from compression.  The head and tail of the list
1202 # are always uncompressed for fast push/pop operations.  Settings are:
1203 # 0: disable all list compression
1204 # 1: depth 1 means "don't start compressing until after 1 node into the list,
1205 #    going from either the head or tail"
1206 #    So: [head]->node->node->...->node->[tail]
1207 #    [head], [tail] will always be uncompressed; inner nodes will compress.
1208 # 2: [head]->[next]->node->node->...->node->[prev]->[tail]
1209 #    2 here means: don't compress head or head->next or tail->prev or tail,
1210 #    but compress all nodes between them.
1211 # 3: [head]->[next]->[next]->node->node->...->node->[prev]->[prev]->[tail]
1212 # etc.
1213 list-compress-depth 0
1214 
1215 # Sets have a special encoding in just one case: when a set is composed
1216 # of just strings that happen to be integers in radix 10 in the range
1217 # of 64 bit signed integers.
1218 # The following configuration setting sets the limit in the size of the
1219 # set in order to use this special memory saving encoding.
1220 set-max-intset-entries 512
1221 
1222 # Similarly to hashes and lists, sorted sets are also specially encoded in
1223 # order to save a lot of space. This encoding is only used when the length and
1224 # elements of a sorted set are below the following limits:
1225 zset-max-ziplist-entries 128
1226 zset-max-ziplist-value 64
1227 
1228 # HyperLogLog sparse representation bytes limit. The limit includes the
1229 # 16 bytes header. When an HyperLogLog using the sparse representation crosses
1230 # this limit, it is converted into the dense representation.
1231 #
1232 # A value greater than 16000 is totally useless, since at that point the
1233 # dense representation is more memory efficient.
1234 #
1235 # The suggested value is ~ 3000 in order to have the benefits of
1236 # the space efficient encoding without slowing down too much PFADD,
1237 # which is O(N) with the sparse encoding. The value can be raised to
1238 # ~ 10000 when CPU is not a concern, but space is, and the data set is
1239 # composed of many HyperLogLogs with cardinality in the 0 - 15000 range.
1240 hll-sparse-max-bytes 3000
1241 
1242 # Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in
1243 # order to help rehashing the main Redis hash table (the one mapping top-level
1244 # keys to values). The hash table implementation Redis uses (see dict.c)
1245 # performs a lazy rehashing: the more operation you run into a hash table
1246 # that is rehashing, the more rehashing "steps" are performed, so if the
1247 # server is idle the rehashing is never complete and some more memory is used
1248 # by the hash table.
1249 #
1250 # The default is to use this millisecond 10 times every second in order to
1251 # actively rehash the main dictionaries, freeing memory when possible.
1252 #
1253 # If unsure:
1254 # use "activerehashing no" if you have hard latency requirements and it is
1255 # not a good thing in your environment that Redis can reply from time to time
1256 # to queries with 2 milliseconds delay.
1257 #
1258 # use "activerehashing yes" if you don't have such hard requirements but
1259 # want to free memory asap when possible.
1260 activerehashing yes
1261 
1262 # The client output buffer limits can be used to force disconnection of clients
1263 # that are not reading data from the server fast enough for some reason (a
1264 # common reason is that a Pub/Sub client can't consume messages as fast as the
1265 # publisher can produce them).
1266 #
1267 # The limit can be set differently for the three different classes of clients:
1268 #
1269 # normal -> normal clients including MONITOR clients
1270 # slave  -> slave clients
1271 # pubsub -> clients subscribed to at least one pubsub channel or pattern
1272 #
1273 # The syntax of every client-output-buffer-limit directive is the following:
1274 #
1275 # client-output-buffer-limit <class> <hard limit> <soft limit> <soft seconds>
1276 #
1277 # A client is immediately disconnected once the hard limit is reached, or if
1278 # the soft limit is reached and remains reached for the specified number of
1279 # seconds (continuously).
1280 # So for instance if the hard limit is 32 megabytes and the soft limit is
1281 # 16 megabytes / 10 seconds, the client will get disconnected immediately
1282 # if the size of the output buffers reach 32 megabytes, but will also get
1283 # disconnected if the client reaches 16 megabytes and continuously overcomes
1284 # the limit for 10 seconds.
1285 #
1286 # By default normal clients are not limited because they don't receive data
1287 # without asking (in a push way), but just after a request, so only
1288 # asynchronous clients may create a scenario where data is requested faster
1289 # than it can read.
1290 #
1291 # Instead there is a default limit for pubsub and slave clients, since
1292 # subscribers and slaves receive data in a push fashion.
1293 #
1294 # Both the hard or the soft limit can be disabled by setting them to zero.
1295 client-output-buffer-limit normal 0 0 0
1296 client-output-buffer-limit slave 256mb 64mb 60
1297 client-output-buffer-limit pubsub 32mb 8mb 60
1298 
1299 # Redis calls an internal function to perform many background tasks, like
1300 # closing connections of clients in timeout, purging expired keys that are
1301 # never requested, and so forth.
1302 #
1303 # Not all tasks are performed with the same frequency, but Redis checks for
1304 # tasks to perform according to the specified "hz" value.
1305 #
1306 # By default "hz" is set to 10. Raising the value will use more CPU when
1307 # Redis is idle, but at the same time will make Redis more responsive when
1308 # there are many keys expiring at the same time, and timeouts may be
1309 # handled with more precision.
1310 #
1311 # The range is between 1 and 500, however a value over 100 is usually not
1312 # a good idea. Most users should use the default of 10 and raise this up to
1313 # 100 only in environments where very low latency is required.
1314 hz 10
1315 
1316 # When a child rewrites the AOF file, if the following option is enabled
1317 # the file will be fsync-ed every 32 MB of data generated. This is useful
1318 # in order to commit the file to the disk more incrementally and avoid
1319 # big latency spikes.
1320 aof-rewrite-incremental-fsync yes
1321 
1322 # Redis LFU eviction (see maxmemory setting) can be tuned. However it is a good
1323 # idea to start with the default settings and only change them after investigating
1324 # how to improve the performances and how the keys LFU change over time, which
1325 # is possible to inspect via the OBJECT FREQ command.
1326 #
1327 # There are two tunable parameters in the Redis LFU implementation: the
1328 # counter logarithm factor and the counter decay time. It is important to
1329 # understand what the two parameters mean before changing them.
1330 #
1331 # The LFU counter is just 8 bits per key, it's maximum value is 255, so Redis
1332 # uses a probabilistic increment with logarithmic behavior. Given the value
1333 # of the old counter, when a key is accessed, the counter is incremented in
1334 # this way:
1335 #
1336 # 1. A random number R between 0 and 1 is extracted.
1337 # 2. A probability P is calculated as 1/(old_value*lfu_log_factor+1).
1338 # 3. The counter is incremented only if R < P.
1339 #
1340 # The default lfu-log-factor is 10. This is a table of how the frequency
1341 # counter changes with a different number of accesses with different
1342 # logarithmic factors:
1343 #
1344 # +--------+------------+------------+------------+------------+------------+
1345 # | factor | 100 hits   | 1000 hits  | 100K hits  | 1M hits    | 10M hits   |
1346 # +--------+------------+------------+------------+------------+------------+
1347 # | 0      | 104        | 255        | 255        | 255        | 255        |
1348 # +--------+------------+------------+------------+------------+------------+
1349 # | 1      | 18         | 49         | 255        | 255        | 255        |
1350 # +--------+------------+------------+------------+------------+------------+
1351 # | 10     | 10         | 18         | 142        | 255        | 255        |
1352 # +--------+------------+------------+------------+------------+------------+
1353 # | 100    | 8          | 11         | 49         | 143        | 255        |
1354 # +--------+------------+------------+------------+------------+------------+
1355 #
1356 # NOTE: The above table was obtained by running the following commands:
1357 #
1358 #   redis-benchmark -n 1000000 incr foo
1359 #   redis-cli object freq foo
1360 #
1361 # NOTE 2: The counter initial value is 5 in order to give new objects a chance
1362 # to accumulate hits.
1363 #
1364 # The counter decay time is the time, in minutes, that must elapse in order
1365 # for the key counter to be divided by two (or decremented if it has a value
1366 # less <= 10).
1367 #
1368 # The default value for the lfu-decay-time is 1. A Special value of 0 means to
1369 # decay the counter every time it happens to be scanned.
1370 #
1371 # lfu-log-factor 10
1372 # lfu-decay-time 1
1373 
1374 ########################### ACTIVE DEFRAGMENTATION #######################
1375 #
1376 # WARNING THIS FEATURE IS EXPERIMENTAL. However it was stress tested
1377 # even in production and manually tested by multiple engineers for some
1378 # time.
1379 #
1380 # What is active defragmentation?
1381 # -------------------------------
1382 #
1383 # Active (online) defragmentation allows a Redis server to compact the
1384 # spaces left between small allocations and deallocations of data in memory,
1385 # thus allowing to reclaim back memory.
1386 #
1387 # Fragmentation is a natural process that happens with every allocator (but
1388 # less so with Jemalloc, fortunately) and certain workloads. Normally a server
1389 # restart is needed in order to lower the fragmentation, or at least to flush
1390 # away all the data and create it again. However thanks to this feature
1391 # implemented by Oran Agra for Redis 4.0 this process can happen at runtime
1392 # in an "hot" way, while the server is running.
1393 #
1394 # Basically when the fragmentation is over a certain level (see the
1395 # configuration options below) Redis will start to create new copies of the
1396 # values in contiguous memory regions by exploiting certain specific Jemalloc
1397 # features (in order to understand if an allocation is causing fragmentation
1398 # and to allocate it in a better place), and at the same time, will release the
1399 # old copies of the data. This process, repeated incrementally for all the keys
1400 # will cause the fragmentation to drop back to normal values.
1401 #
1402 # Important things to understand:
1403 #
1404 # 1. This feature is disabled by default, and only works if you compiled Redis
1405 #    to use the copy of Jemalloc we ship with the source code of Redis.
1406 #    This is the default with Linux builds.
1407 #
1408 # 2. You never need to enable this feature if you don't have fragmentation
1409 #    issues.
1410 #
1411 # 3. Once you experience fragmentation, you can enable this feature when
1412 #    needed with the command "CONFIG SET activedefrag yes".
1413 #
1414 # The configuration parameters are able to fine tune the behavior of the
1415 # defragmentation process. If you are not sure about what they mean it is
1416 # a good idea to leave the defaults untouched.
1417 
1418 # Enabled active defragmentation
1419 # activedefrag yes
1420 
1421 # Minimum amount of fragmentation waste to start active defrag
1422 # active-defrag-ignore-bytes 100mb
1423 
1424 # Minimum percentage of fragmentation to start active defrag
1425 # active-defrag-threshold-lower 10
1426 
1427 # Maximum percentage of fragmentation at which we use maximum effort
1428 # active-defrag-threshold-upper 100
1429 
1430 # Minimal effort for defrag in CPU percentage
1431 # active-defrag-cycle-min 25
1432 
1433 # Maximal effort for defrag in CPU percentage
1434 # active-defrag-cycle-max 75
redis.conf

参考博客:

https://www.cnblogs.com/joshua317/p/5635297.html

http://blog.csdn.net/ljl890705/article/details/51540427