redis.conf介绍2
本文转载自：http://blog.csdn.net/spring21st/article/details/11176723
001 # Redis configuration file example 002 003 # Note on units: when memory size is needed, it is possible to specifiy 004 # it in the usual form of 1k 5GB 4M and so forth: 005 # 006 # 1k => 1000 bytes 007 # 1kb => 1024 bytes 008 # 1m => 1000000 bytes 009 # 1mb => 1024*1024 bytes 010 # 1g => 1000000000 bytes 011 # 1gb => 1024*1024*1024 bytes 012 # 013 # units are case insensitive so 1GB 1Gb 1gB are all the same. 014 015 # By default Redis does not run as a daemon. Use 'yes' if you need it. 016 # Note that Redis will write a pid file in /var/run/redis.pid when daemonized. 017 daemonize no 018 Redis默认不是以守护进程的方式运行，可以通过该配置项修改，使用yes启用守护进程 019 020 # When running daemonized, Redis writes a pid file in /var/run/redis.pid by 021 # default. You can specify a custom pid file location here. 022 pidfile /var/run/redis.pid 023 当Redis以守护进程方式运行时，Redis默认会把pid写入/var/run/redis.pid文件，可以通过pidfile指定 024 # Accept connections on the specified port, default is 6379. 025 # If port 0 is specified Redis will not listen on a TCP socket. 026 port 6379 027 指定Redis监听端口，默认端口为6379 028 # If you want you can bind a single interface, if the bind option is not 029 # specified all the interfaces will listen for incoming connections. 030 # 031 # bind 127.0.0.1 032 绑定的主机地址 033 # Specify the path for the unix socket that will be used to listen for 034 # incoming connections. There is no default, so Redis will not listen 035 # on a unix socket when not specified. www.2cto.com 036 # 037 # unixsocket /tmp/redis.sock 038 # unixsocketperm 755 039 040 # Close the connection after a client is idle for N seconds (0 to disable) 041 timeout 0 042 当 客户端闲置多长时间后关闭连接，如果指定为0，表示关闭该功能 043 # Set server verbosity to 'debug' 044 # it can be one of: 045 # debug (a lot of information, useful for development/testing) 046 # verbose (many rarely useful info, but not a mess like the debug level) 047 # notice (moderately verbose, what you want in production probably) 048 # warning (only very important / critical messages are logged) 049 loglevel verbose 050 指定日志记录级别，Redis总共支持四个级别：debug、verbose、notice、warning，默认为verbose 051 # Specify the log file name. Also 'stdout' can be used to force 052 # Redis to log on the standard output. Note that if you use standard 053 # output for logging but daemonize, logs will be sent to /dev/null 054 logfile stdout 055 日志记录方式，默认为标准输出，如果配置Redis为守护进程方式运行，而这里又配置为日志记录方式为标准输出，则日志将会发送给/dev/null 056 # To enable logging to the system logger, just set 'syslog-enabled' to yes, 057 # and optionally update the other syslog parameters to suit your needs. 058 # syslog-enabled no 059 060 # Specify the syslog identity. 061 # syslog-ident redis 062 063 # Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7. 064 # syslog-facility local0 065 066 # Set the number of databases. The default database is DB 0, you can select 067 # a different one on a per-connection basis using SELECT <dbid> where 068 # dbid is a number between 0 and 'databases'-1 069 databases 16 www.2cto.com 070 设置数据库的数量，默认数据库为0，可以使用SELECT <dbid>命令在连接上指定数据库id 071 ################################ SNAPSHOTTING ################################# 072 # 073 # Save the DB on disk: 074 # 075 # save <seconds> <changes> 076 # 077 # Will save the DB if both the given number of seconds and the given 078 # number of write operations against the DB occurred. 079 # 080 # In the example below the behaviour will be to save: 081 # after 900 sec (15 min) if at least 1 key changed 082 # after 300 sec (5 min) if at least 10 keys changed 083 # after 60 sec if at least 10000 keys changed 084 # 085 # Note: you can disable saving at all commenting all the "save" lines. 086 087 save 900 1 088 save 300 10 089 save 60 10000 090 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。 091 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 092 # Compress string objects using LZF when dump .rdb databases? 093 # For default that's set to 'yes' as it's almost always a win. 094 # If you want to save some CPU in the saving child set it to 'no' but 095 # the dataset will likely be bigger if you have compressible values or keys. 096 rdbcompression yes 097 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，但会导致数据库文件变的巨大 098 # The filename where to dump the DB 099 dbfilename dump.rdb 100 指定本地数据库文件名，默认值为dump.rdb 101 # The working directory. 102 # 103 # The DB will be written inside this directory, with the filename specified 104 # above using the 'dbfilename' configuration directive. 105 # 106 # Also the Append Only File will be created inside this directory. 107 # 108 # Note that you must specify a directory here, not a file name. 109 dir ./ 110 指定本地数据库存放目录 111 ################################# REPLICATION ################################# 112 113 # Master-Slave replication. Use slaveof to make a Redis instance a copy of 114 # another Redis server. Note that the configuration is local to the slave 115 # so for example it is possible to configure the slave to save the DB with a 116 # different interval, or to listen to another port, and so on. www.2cto.com 117 # 118 # slaveof <masterip> <masterport> 119 slaveof <masterip> <masterport> 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 120 # If the master is password protected (using the "requirepass" configuration 121 # directive below) it is possible to tell the slave to authenticate before 122 # starting the replication synchronization process, otherwise the master will 123 # refuse the slave request. 124 # 125 # masterauth <master-password> 126 masterauth <master-password> 当master服务设置了密码保护时，slav服务连接master的密码 127 # When a slave lost the connection with the master, or when the replication 128 # is still in progress, the slave can act in two different ways: 129 # 130 # 1) if slave-serve-stale-data is set to 'yes' (the default) the slave will 131 # still reply to client requests, possibly with out of data data, or the 132 # data set may just be empty if this is the first synchronization. 133 # 134 # 2) if slave-serve-stale data is set to 'no' the slave will reply with 135 # an error "SYNC with master in progress" to all the kind of commands 136 # but to INFO and SLAVEOF. 137 # 138 slave-serve-stale-data yes 139 140 # Slaves send PINGs to server in a predefined interval. It's possible to change 141 # this interval with the repl_ping_slave_period option. The default value is 10 142 # seconds. www.2cto.com 143 # 144 # repl-ping-slave-period 10 145 146 # The following option sets a timeout for both Bulk transfer I/O timeout and 147 # master data or ping response timeout. The default value is 60 seconds. 148 # 149 # It is important to make sure that this value is greater than the value 150 # specified for repl-ping-slave-period otherwise a timeout will be detected 151 # every time there is low traffic between the master and the slave. 152 # 153 # repl-timeout 60 154 155 ################################## SECURITY ################################### 156 157 # Require clients to issue AUTH <PASSWORD> before processing any other 158 # commands. This might be useful in environments in which you do not trust 159 # others with access to the host running redis-server. 160 # 161 # This should stay commented out for backward compatibility and because most 162 # people do not need auth (e.g. they run their own servers). 163 # 164 # Warning: since Redis is pretty fast an outside user can try up to 165 # 150k passwords per second against a good box. This means that you should 166 # use a very strong password otherwise it will be very easy to break. 167 # 168 # requirepass foobared 169 requirepass foobared 设置Redis连接密码，如果配置了连接密码，客户端在连接Redis时需要通过AUTH <password>命令提供密码，默认关闭 170 # Command renaming. 171 # 172 # It is possilbe to change the name of dangerous commands in a shared 173 # environment. For instance the CONFIG command may be renamed into something 174 # of hard to guess so that it will be still available for internal-use 175 # tools but not available for general clients. 176 # 177 # Example: 178 # 179 # rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52 180 # 181 # It is also possilbe to completely kill a command renaming it into 182 # an empty string: 183 # 184 # rename-command CONFIG "" 185 186 ################################### LIMITS #################################### 187 188 # Set the max number of connected clients at the same time. By default there 189 # is no limit, and it's up to the number of file descriptors the Redis process 190 # is able to open. The special value '0' means no limits. 191 # Once the limit is reached Redis will close all the new connections sending 192 # an error 'max number of clients reached'. www.2cto.com 193 # 194 # maxclients 128 195 maxclients 128 设置同一时间最大客户端连接数，默认无限制，Redis可以同时打开的客户端连接数为Redis进程可以打开的最大文件描述符数，如果设置 maxclients 0，表示不作限制。当客户端连接数到达限制时，Redis会关闭新的连接并向客户端返回max number of clients reached错误信息 196 # Don't use more memory than the specified amount of bytes. 197 # When the memory limit is reached Redis will try to remove keys with an 198 # EXPIRE set. It will try to start freeing keys that are going to expire 199 # in little time and preserve keys with a longer time to live. 200 # Redis will also try to remove objects from free lists if possible. 201 # 202 # If all this fails, Redis will start to reply with errors to commands 203 # that will use more memory, like SET, LPUSH, and so on, and will continue 204 # to reply to most read-only commands like GET. 205 # 206 # WARNING: maxmemory can be a good idea mainly if you want to use Redis as a 207 # 'state' server or cache, not as a real DB. When Redis is used as a real 208 # database the memory usage will grow over the weeks, it will be obvious if 209 # it is going to use too much memory in the long run, and you'll have the time 210 # to upgrade. With maxmemory after the limit is reached you'll start to get 211 # errors for write operations, and this may even lead to DB inconsistency. 212 # 213 # maxmemory <bytes> 214 maxmemory <bytes>指定Redis最大内存限制，Redis在启动时会把数据加载到内存中，达到最大内存后，Redis会先尝试清除已到期或即将到期的Key，当此方法处理 后，仍然到达最大内存设置，将无法再进行写入操作，但仍然可以进行读取操作。Redis新的vm机制，会把Key存放内存，Value会存放在swap区 215 # MAXMEMORY POLICY: how Redis will select what to remove when maxmemory 216 # is reached? You can select among five behavior: 217 # 218 # volatile-lru -> remove the key with an expire set using an LRU algorithm 219 # allkeys-lru -> remove any key accordingly to the LRU algorithm 220 # volatile-random -> remove a random key with an expire set 221 # allkeys->random -> remove a random key, any key 222 # volatile-ttl -> remove the key with the nearest expire time (minor TTL) 223 # noeviction -> don't expire at all, just return an error on write operations 224 # 225 # Note: with all the kind of policies, Redis will return an error on write 226 # operations, when there are not suitable keys for eviction. 227 # 228 # At the date of writing this commands are: set setnx setex append 229 # incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd 230 # sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby 231 # zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby 232 # getset mset msetnx exec sort www.2cto.com 233 # 234 # The default is: 235 # 236 # maxmemory-policy volatile-lru 237 238 # LRU and minimal TTL algorithms are not precise algorithms but approximated 239 # algorithms (in order to save memory), so you can select as well the sample 240 # size to check. For instance for default Redis will check three keys and 241 # pick the one that was used less recently, you can change the sample size 242 # using the following configuration directive. 243 # 244 # maxmemory-samples 3 245 246 ############################## APPEND ONLY MODE ############################### 247 248 # By default Redis asynchronously dumps the dataset on disk. If you can live 249 # with the idea that the latest records will be lost if something like a crash 250 # happens this is the preferred way to run Redis. If instead you care a lot 251 # about your data and don't want to that a single record can get lost you should 252 # enable the append only mode: when this mode is enabled Redis will append 253 # every write operation received in the file appendonly.aof. This file will 254 # be read on startup in order to rebuild the full dataset in memory. 255 # 256 # Note that you can have both the async dumps and the append only file if you 257 # like (you have to comment the "save" statements above to disable the dumps). 258 # Still if append only mode is enabled Redis will load the data from the 259 # log file at startup ignoring the dump.rdb file. 260 # 261 # IMPORTANT: Check the BGREWRITEAOF to check how to rewrite the append 262 # log file in background when it gets too big. 263 264 appendonly no 265 appendonly no指定是否在每次更新操作后进行日志记录，Redis在默认情况下是异步的把数据写入磁盘，如果不开启，可能会在断电时导致一段时间内的数据丢失。因为 redis本身同步数据文件是按上面save条件来同步的，所以有的数据会在一段时间内只存在于内存中。默认为no 266 # The name of the append only file (default: "appendonly.aof") 267 # appendfilename appendonly.aof 268 appendfilename appendonly.aof指定更新日志文件名，默认为appendonly.aof 269 # The fsync() call tells the Operating System to actually write data on disk 270 # instead to wait for more data in the output buffer. Some OS will really flush 271 # data on disk, some other OS will just try to do it ASAP. 272 # 273 # Redis supports three different modes: 274 # 275 # no: don't fsync, just let the OS flush the data when it wants. Faster. 276 # always: fsync after every write to the append only log . Slow, Safest. 277 # everysec: fsync only if one second passed since the last fsync. Compromise. 278 # 279 # The default is "everysec" that's usually the right compromise between 280 # speed and data safety. It's up to you to understand if you can relax this to 281 # "no" that will will let the operating system flush the output buffer when 282 # it wants, for better performances (but if you can live with the idea of 283 # some data loss consider the default persistence mode that's snapshotting), 284 # or on the contrary, use "always" that's very slow but a bit safer than 285 # everysec. www.2cto.com 286 # 287 # If unsure, use "everysec". 288 289 # appendfsync always 290 appendfsync everysec 291 # appendfsync no 292 指定更新日志条件，共有3个可选值： 293 no：表示等操作系统进行数据缓存同步到磁盘（快） 294 always：表示每次更新操作后手动调用fsync()将数据写到磁盘（慢，安全） 295 everysec：表示每秒同步一次（折衷，默认值） 296 # When the AOF fsync policy is set to always or everysec, and a background 297 # saving process (a background save or AOF log background rewriting) is 298 # performing a lot of I/O against the disk, in some Linux configurations 299 # Redis may block too long on the fsync() call. Note that there is no fix for 300 # this currently, as even performing fsync in a different thread will block 301 # our synchronous write(2) call. 302 # 303 # In order to mitigate this problem it's possible to use the following option 304 # that will prevent fsync() from being called in the main process while a 305 # BGSAVE or BGREWRITEAOF is in progress. 306 # 307 # This means that while another child is saving the durability of Redis is 308 # the same as "appendfsync none", that in pratical terms means that it is 309 # possible to lost up to 30 seconds of log in the worst scenario (with the 310 # default Linux settings). 311 # 312 # If you have latency problems turn this to "yes". Otherwise leave it as 313 # "no" that is the safest pick from the point of view of durability. 314 no-appendfsync-on-rewrite no 315 316 # Automatic rewrite of the append only file. 317 # Redis is able to automatically rewrite the log file implicitly calling 318 # BGREWRITEAOF when the AOF log size will growth by the specified percentage. 319 # 320 # This is how it works: Redis remembers the size of the AOF file after the 321 # latest rewrite (or if no rewrite happened since the restart, the size of 322 # the AOF at startup is used). 323 # 324 # This base size is compared to the current size. If the current size is 325 # bigger than the specified percentage, the rewrite is triggered. Also 326 # you need to specify a minimal size for the AOF file to be rewritten, this 327 # is useful to avoid rewriting the AOF file even if the percentage increase 328 # is reached but it is still pretty small. 329 # 330 # Specify a precentage of zero in order to disable the automatic AOF 331 # rewrite feature. www.2cto.com 332 333 auto-aof-rewrite-percentage 100 334 auto-aof-rewrite-min-size 64mb 335 336 ################################## SLOW LOG ################################### 337 338 # The Redis Slow Log is a system to log queries that exceeded a specified 339 # execution time. The execution time does not include the I/O operations 340 # like talking with the client, sending the reply and so forth, 341 # but just the time needed to actually execute the command (this is the only 342 # stage of command execution where the thread is blocked and can not serve 343 # other requests in the meantime). 344 # 345 # You can configure the slow log with two parameters: one tells Redis 346 # what is the execution time, in microseconds, to exceed in order for the 347 # command to get logged, and the other parameter is the length of the 348 # slow log. When a new command is logged the oldest one is removed from the 349 # queue of logged commands. 350 351 # The following time is expressed in microseconds, so 1000000 is equivalent 352 # to one second. Note that a negative number disables the slow log, while 353 # a value of zero forces the logging of every command. 354 slowlog-log-slower-than 10000 355 356 # There is no limit to this length. Just be aware that it will consume memory. 357 # You can reclaim memory used by the slow log with SLOWLOG RESET. 358 slowlog-max-len 1024 359 360 ################################ VIRTUAL MEMORY ############################### 361 362 ### WARNING! Virtual Memory is deprecated in Redis 2.4 363 ### The use of Virtual Memory is strongly discouraged. 364 365 ### WARNING! Virtual Memory is deprecated in Redis 2.4 366 ### The use of Virtual Memory is strongly discouraged. 367 368 # Virtual Memory allows Redis to work with datasets bigger than the actual 369 # amount of RAM needed to hold the whole dataset in memory. 370 # In order to do so very used keys are taken in memory while the other keys 371 # are swapped into a swap file, similarly to what operating systems do 372 # with memory pages. www.2cto.com 373 # 374 # To enable VM just set 'vm-enabled' to yes, and set the following three 375 # VM parameters accordingly to your needs. 376 377 vm-enabled no 378 指定是否启用虚拟内存机制，默认值为no，简单的介绍一下，VM机制将数据分页存放，由Redis将访问量较少的页即冷数据swap到磁盘上，访问多的页面由磁盘自动换出到内存中（在后面的文章我会仔细分析Redis的VM机制） 379 # vm-enabled yes 380 381 # This is the path of the Redis swap file. As you can guess, swap files 382 # can't be shared by different Redis instances, so make sure to use a swap 383 # file for every redis process you are running. Redis will complain if the 384 # swap file is already in use. 385 # 386 # The best kind of storage for the Redis swap file (that's accessed at random) 387 # is a Solid State Disk (SSD). 388 # 389 # *** WARNING *** if you are using a shared hosting the default of putting 390 # the swap file under /tmp is not secure. Create a dir with access granted 391 # only to Redis user and configure Redis to create the swap file there. 392 vm-swap-file /tmp/redis.swap 393 虚拟内存文件路径，默认值为/tmp/redis.swap，不可多个Redis实例共享 394 # vm-max-memory configures the VM to use at max the specified amount of 395 # RAM. Everything that deos not fit will be swapped on disk *if* possible, that 396 # is, if there is still enough contiguous space in the swap file. 397 # 398 # With vm-max-memory 0 the system will swap everything it can. Not a good 399 # default, just specify the max amount of RAM you can in bytes, but it's 400 # better to leave some margin. For instance specify an amount of RAM 401 # that's more or less between 60 and 80% of your free RAM. 402 vm-max-memory 0 www.2cto.com 403 将所有大于vm-max-memory的数据存入虚拟内存,无论vm-max-memory设置多小,所有索引数据都是内存存储的(Redis的索引数据 就是keys),也就是说,当vm-max-memory设置为0的时候,其实是所有value都存在于磁盘。默认值为0 404 # Redis swap files is split into pages. An object can be saved using multiple 405 # contiguous pages, but pages can't be shared between different objects. 406 # So if your page is too big, small objects swapped out on disk will waste 407 # a lot of space. If you page is too small, there is less space in the swap 408 # file (assuming you configured the same number of total swap file pages). 409 # 410 # If you use a lot of small objects, use a page size of 64 or 32 bytes. 411 # If you use a lot of big objects, use a bigger page size. 412 # If unsure, use the default :) 413 vm-page-size 32 414 Redis swap文件分成了很多的page，一个对象可以保存在多个page上面，但一个page上不能被多个对象共享，vm-page-size是要根据存储的 数据大小来设定的，作者建议如果存储很多小对象，page大小最好设置为32或者64bytes；如果存储很大大对象，则可以使用更大的page，如果不 确定，就使用默认值 415 # Number of total memory pages in the swap file. 416 # Given that the page table (a bitmap of free/used pages) is taken in memory, 417 # every 8 pages on disk will consume 1 byte of RAM. 418 # 419 # The total swap size is vm-page-size * vm-pages 420 # 421 # With the default of 32-bytes memory pages and 134217728 pages Redis will 422 # use a 4 GB swap file, that will use 16 MB of RAM for the page table. 423 # 424 # It's better to use the smallest acceptable value for your application, 425 # but the default is large in order to work in most conditions. 426 vm-pages 134217728 427 设置swap文件中的page数量，由于页表（一种表示页面空闲或使用的bitmap）是在放在内存中的，，在磁盘上每8个pages将消耗1byte的内存。 428 # Max number of VM I/O threads running at the same time. 429 # This threads are used to read/write data from/to swap file, since they 430 # also encode and decode objects from disk to memory or the reverse, a bigger 431 # number of threads can help with big objects even if they can't help with 432 # I/O itself as the physical device may not be able to couple with many 433 # reads/writes operations at the same time. www.2cto.com 434 # 435 # The special value of 0 turn off threaded I/O and enables the blocking 436 # Virtual Memory implementation. 437 vm-max-threads 4 438 设置访问swap文件的线程数,最好不要超过机器的核数,如果设置为0,那么所有对swap文件的操作都是串行的，可能会造成比较长时间的延迟。默认值为4 439 ############################### ADVANCED CONFIG ############################### 440 441 # Hashes are encoded in a special way (much more memory efficient) when they 442 # have at max a given numer of elements, and the biggest element does not 443 # exceed a given threshold. You can configure this limits with the following 444 # configuration directives. 445 hash-max-zipmap-entries 512 446 hash-max-zipmap-value 64 447 指定在超过一定的数量或者最大的元素超过某一临界值时，采用一种特殊的哈希算法 448 # Similarly to hashes, small lists are also encoded in a special way in order 449 # to save a lot of space. The special representation is only used when 450 # you are under the following limits: 451 list-max-ziplist-entries 512 452 list-max-ziplist-value 64 453 454 # Sets have a special encoding in just one case: when a set is composed 455 # of just strings that happens to be integers in radix 10 in the range 456 # of 64 bit signed integers. 457 # The following configuration setting sets the limit in the size of the 458 # set in order to use this special memory saving encoding. 459 set-max-intset-entries 512 www.2cto.com 460 461 # Similarly to hashes and lists, sorted sets are also specially encoded in 462 # order to save a lot of space. This encoding is only used when the length and 463 # elements of a sorted set are below the following limits: 464 zset-max-ziplist-entries 128 465 zset-max-ziplist-value 64 466 467 # Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in 468 # order to help rehashing the main Redis hash table (the one mapping top-level 469 # keys to values). The hash table implementation redis uses (see dict.c) 470 # performs a lazy rehashing: the more operation you run into an hash table 471 # that is rhashing, the more rehashing "steps" are performed, so if the 472 # server is idle the rehashing is never complete and some more memory is used 473 # by the hash table. 474 # 475 # The default is to use this millisecond 10 times every second in order to 476 # active rehashing the main dictionaries, freeing memory when possible. 477 # 478 # If unsure: 479 # use "activerehashing no" if you have hard latency requirements and it is 480 # not a good thing in your environment that Redis can reply form time to time 481 # to queries with 2 milliseconds delay. 482 # 483 # use "activerehashing yes" if you don't have such hard requirements but 484 # want to free memory asap when possible. 485 activerehashing yes www.2cto.com 486 487 ################################## INCLUDES ################################### 488 489 # Include one or more other config files here. This is useful if you 490 # have a standard template that goes to all redis server but also need 491 # to customize a few per-server settings. Include files can include 492 # other files, so use this wisely. 493 # 494 # include /path/to/local.conf 495 # include /path/to/other.conf 496
