原文連結：redis.conf配置詳細解析

# redis 配置檔案示例 # 當你需要為某個配置項指定記憶體大小的時候，必須要帶上單位， # 通常的格式就是 1k 5gb 4m 等醬紫： # # 1k => 1000 bytes # 1kb => 1024 bytes # 1m => 1000000 bytes # 1mb => 1024*1024 bytes # 1g => 1000000000 bytes # 1gb => 1024*1024*1024 bytes # # 單位是不區分大小寫的，你寫 1K 5GB 4M 也行 ################################## INCLUDES ################################### # 假如說你有一個可用於所有的 redis server 的標準配置模板， # 但針對某些 server 又需要一些個性化的設定， # 你可以使用 include 來包含一些其他的配置檔案，這對你來說是非常有用的。 # # 但是要注意哦，include 是不能被 config rewrite 命令改寫的 # 由於 redis 總是以最後的加工線作為一個配置指令值，所以你最好是把 include 放在這個檔案的最前面， # 以避免在執行時覆蓋配置的改變，相反，你就把它放在後面（外國人真囉嗦）。 # # include /path/to/local.conf # include /path/to/other.conf ################################ 常用 ##################################### # 預設情況下 redis 不是作為守護程序執行的，如果你想讓它在後臺執行，你就把它改成 yes。 # 當redis作為守護程序執行的時候，它會寫一個 pid 到 /var/run/redis.pid 檔案裡面。 daemonize no # 當redis作為守護程序執行的時候，它會把 pid 預設寫到 /var/run/redis.pid 檔案裡面， # 但是你可以在這裡自己制定它的檔案位置。 pidfile /var/run/redis.pid # 監聽埠號，預設為 6379，如果你設為 0 ，redis 將不在 socket 上監聽任何客戶端連線。 port 6379 # TCP 監聽的最大容納數量 # # 在高併發的環境下，你需要把這個值調高以避免客戶端連線緩慢的問題。 # Linux 核心會一聲不響的把這個值縮小成 /proc/sys/net/core/somaxconn 對應的值， # 所以你要修改這兩個值才能達到你的預期。 tcp-backlog 511 # 預設情況下，redis 在 server 上所有有效的網路介面上監聽客戶端連線。 # 你如果只想讓它在一個網路介面上監聽，那你就繫結一個IP或者多個IP。 # # 示例，多個IP用空格隔開: # # bind 192.168.1.100 10.0.0.1 # bind 127.0.0.1 # 指定 unix socket 的路徑。 # # unixsocket /tmp/redis.sock # unixsocketperm 755 # 指定在一個 client 空閒多少秒之後關閉連線（0 就是不管它） timeout 0 # tcp 心跳包。 # # 如果設定為非零，則在與客戶端缺乏通訊的時候使用 SO_KEEPALIVE 傳送 tcp acks 給客戶端。 # 這個之所有有用，主要由兩個原因： # # 1) 防止死的 peers # 2) Take the connection alive from the point of view of network # equipment in the middle. # # On Linux, the specified value (in seconds) is the period used to send ACKs. # Note that to close the connection the double of the time is needed. # On other kernels the period depends on the kernel configuration. # # A reasonable value for this option is 60 seconds. # 推薦一個合理的值就是60秒 tcp-keepalive 0 # 定義日誌級別。 # 可以是下面的這些值： # debug (適用於開發或測試階段) # verbose (many rarely useful info, but not a mess like the debug level) # notice (適用於生產環境) # warning (僅僅一些重要的訊息被記錄) loglevel notice # 指定日誌檔案的位置 logfile "" # 要想把日誌記錄到系統日誌，就把它改成 yes， # 也可以可選擇性的更新其他的syslog 引數以達到你的要求 # syslog-enabled no # 設定 syslog 的 identity。 # syslog-ident redis # 設定 syslog 的 facility，必須是 USER 或者是 LOCAL0-LOCAL7 之間的值。 # syslog-facility local0 # 設定資料庫的數目。 # 預設資料庫是 DB 0，你可以在每個連線上使用 select <dbid> 命令選擇一個不同的資料庫， # 但是 dbid 必須是一個介於 0 到 databasees - 1 之間的值 databases 16 ################################ 快照 ################################ # # 存 DB 到磁碟： # # 格式：save <間隔時間（秒）> <寫入次數> # # 根據給定的時間間隔和寫入次數將資料儲存到磁碟 # # 下面的例子的意思是： # 900 秒內如果至少有 1 個 key 的值變化，則儲存 # 300 秒內如果至少有 10 個 key 的值變化，則儲存 # 60 秒內如果至少有 10000 個 key 的值變化，則儲存 #　　 # 注意：你可以註釋掉所有的 save 行來停用儲存功能。 # 也可以直接一個空字串來實現停用： # save "" save 900 1 save 300 10 save 60 10000 # 預設情況下，如果 redis 最後一次的後臺儲存失敗，redis 將停止接受寫操作， # 這樣以一種強硬的方式讓使用者知道資料不能正確的持久化到磁碟， # 否則就會沒人注意到災難的發生。 # # 如果後臺儲存程序重新啟動工作了，redis 也將自動的允許寫操作。 # # 然而你要是安裝了靠譜的監控，你可能不希望 redis 這樣做，那你就改成 no 好了。 stop-writes-on-bgsave-error yes # 是否在 dump .rdb 資料庫的時候使用 LZF 壓縮字串 # 預設都設為 yes # 如果你希望儲存子程序節省點 cpu ，你就設定它為 no ， # 不過這個資料集可能就會比較大 rdbcompression yes # 是否校驗rdb檔案 rdbchecksum yes # 設定 dump 的檔案位置 dbfilename dump.rdb # 工作目錄 # 例如上面的 dbfilename 只指定了檔名， # 但是它會寫入到這個目錄下。這個配置項一定是個目錄，而不能是檔名。 dir ./ ################################# 主從複製 ################################# # 主從複製。使用 slaveof 來讓一個 redis 例項成為另一個reids 例項的副本。 # 注意這個只需要在 slave 上配置。 # # slaveof <masterip> <masterport> # 如果 master 需要密碼認證，就在這裡設定 # masterauth <master-password> # 當一個 slave 與 master 失去聯絡，或者複製正在進行的時候， # slave 可能會有兩種表現： # # 1) 如果為 yes ，slave 仍然會應答客戶端請求，但返回的資料可能是過時， # 或者資料可能是空的在第一次同步的時候 # # 2) 如果為 no ，在你執行除了 info he salveof 之外的其他命令時， # slave 都將返回一個 "SYNC with master in progress" 的錯誤， # slave-serve-stale-data yes # 你可以配置一個 slave 實體是否接受寫入操作。 # 通過寫入操作來儲存一些短暫的資料對於一個 slave 例項來說可能是有用的， # 因為相對從 master 重新同步數而言，據資料寫入到 slave 會更容易被刪除。 # 但是如果客戶端因為一個錯誤的配置寫入，也可能會導致一些問題。 # # 從 redis 2.6 版起，預設 slaves 都是隻讀的。 # # Note: read only slaves are not designed to be exposed to untrusted clients # on the internet. It's just a protection layer against misuse of the instance. # Still a read only slave exports by default all the administrative commands # such as CONFIG, DEBUG, and so forth. To a limited extent you can improve # security of read only slaves using 'rename-command' to shadow all the # administrative / dangerous commands. # 注意：只讀的 slaves 沒有被設計成在 internet 上暴露給不受信任的客戶端。 # 它僅僅是一個針對誤用例項的一個保護層。 slave-read-only yes # Slaves 在一個預定義的時間間隔內傳送 ping 命令到 server 。 # 你可以改變這個時間間隔。預設為 10 秒。 # # repl-ping-slave-period 10 # The following option sets the replication timeout for: # 設定主從複製過期時間 # # 1) Bulk transfer I/O during SYNC, from the point of view of slave. # 2) Master timeout from the point of view of slaves (data, pings). # 3) Slave timeout from the point of view of masters (REPLCONF ACK pings). # # It is important to make sure that this value is greater than the value # specified for repl-ping-slave-period otherwise a timeout will be detected # every time there is low traffic between the master and the slave. # 這個值一定要比 repl-ping-slave-period 大 # # repl-timeout 60 # Disable TCP_NODELAY on the slave socket after SYNC? # # If you select "yes" Redis will use a smaller number of TCP packets and # less bandwidth to send data to slaves. But this can add a delay for # the data to appear on the slave side, up to 40 milliseconds with # Linux kernels using a default configuration. # # If you select "no" the delay for data to appear on the slave side will # be reduced but more bandwidth will be used for replication. # # By default we optimize for low latency, but in very high traffic conditions # or when the master and slaves are many hops away, turning this to "yes" may # be a good idea. repl-disable-tcp-nodelay no # 設定主從複製容量大小。這個 backlog 是一個用來在 slaves 被斷開連線時 # 存放 slave 資料的 buffer，所以當一個 slave 想要重新連線，通常不希望全部重新同步， # 只是部分同步就夠了，僅僅傳遞 slave 在斷開連線時丟失的這部分資料。 # # The biggest the replication backlog, the longer the time the slave can be # disconnected and later be able to perform a partial resynchronization. # 這個值越大，salve 可以斷開連線的時間就越長。 # # The backlog is only allocated once there is at least a slave connected. # # repl-backlog-size 1mb # After a master has no longer connected slaves for some time, the backlog # will be freed. The following option configures the amount of seconds that # need to elapse, starting from the time the last slave disconnected, for # the backlog buffer to be freed. # 在某些時候，master 不再連線 slaves，backlog 將被釋放。 # # A value of 0 means to never release the backlog. # 如果設定為 0 ，意味著絕不釋放 backlog 。 # # repl-backlog-ttl 3600 # 當 master 不能正常工作的時候，Redis Sentinel 會從 slaves 中選出一個新的 master， # 這個值越小，就越會被優先選中，但是如果是 0 ， 那是意味著這個 slave 不可能被選中。 # # 預設優先順序為 100。 slave-priority 100 # It is possible for a master to stop accepting writes if there are less than # N slaves connected, having a lag less or equal than M seconds. # # The N slaves need to be in "online" state. # # The lag in seconds, that must be <= the specified value, is calculated from # the last ping received from the slave, that is usually sent every second. # # This option does not GUARANTEES that N replicas will accept the write, but # will limit the window of exposure for lost writes in case not enough slaves # are available, to the specified number of seconds. # # For example to require at least 3 slaves with a lag <= 10 seconds use: # # min-slaves-to-write 3 # min-slaves-max-lag 10 # # Setting one or the other to 0 disables the feature. # # By default min-slaves-to-write is set to 0 (feature disabled) and # min-slaves-max-lag is set to 10. ################################## 安全 ################################### # Require clients to issue AUTH <PASSWORD> before processing any other # commands. This might be useful in environments in which you do not trust # others with access to the host running redis-server. # # This should stay commented out for backward compatibility and because most # people do not need auth (e.g. they run their own servers). # # Warning: since Redis is pretty fast an outside user can try up to # 150k passwords per second against a good box. This means that you should # use a very strong password otherwise it will be very easy to break. # # 設定認證密碼 # requirepass foobared # Command renaming. # # It is possible to change the name of dangerous commands in a shared # environment. For instance the CONFIG command may be renamed into something # hard to guess so that it will still be available for internal-use tools # but not available for general clients. # # Example: # # rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52 # # It is also possible to completely kill a command by renaming it into # an empty string: # # rename-command CONFIG "" # # Please note that changing the name of commands that are logged into the # AOF file or transmitted to slaves may cause problems. ################################### 限制 #################################### # Set the max number of connected clients at the same time. By default # this limit is set to 10000 clients, however if the Redis server is not # able to configure the process file limit to allow for the specified limit # the max number of allowed clients is set to the current file limit # minus 32 (as Redis reserves a few file descriptors for internal uses). # # 一旦達到最大限制，redis 將關閉所有的新連線 # 併發送一個‘max number of clients reached’的錯誤。 # # maxclients 10000 # 如果你設定了這個值，當快取的資料容量達到這個值， redis 將根據你選擇的 # eviction 策略來移除一些 keys。 # # 如果 redis 不能根據策略移除 keys ，或者是策略被設定為 ‘noeviction’， # redis 將開始響應錯誤給命令，如 set，lpush 等等， # 並繼續響應只讀的命令，如 get # # This option is usually useful when using Redis as an LRU cache, or to set # a hard memory limit for an instance (using the 'noeviction' policy). # # WARNING: If you have slaves attached to an instance with maxmemory on, # the size of the output buffers needed to feed the slaves are subtracted # from the used memory count, so that network problems / resyncs will # not trigger a loop where keys are evicted, and in turn the output # buffer of slaves is full with DELs of keys evicted triggering the deletion # of more keys, and so forth until the database is completely emptied. # # In short... if you have slaves attached it is suggested that you set a lower # limit for maxmemory so that there is some free RAM on the system for slave # output buffers (but this is not needed if the policy is 'noeviction'). # # 最大使用記憶體 # maxmemory <bytes> # 最大記憶體策略，你有 5 個選擇。 # # volatile-lru -> remove the key with an expire set using an LRU algorithm # volatile-lru -> 使用 LRU 演算法移除包含過期設定的 key 。 # allkeys-lru -> remove any key accordingly to the LRU algorithm # allkeys-lru -> 根據 LRU 演算法移除所有的 key 。 # volatile-random -> remove a random key with an expire set # allkeys-random -> remove a random key, any key # volatile-ttl -> remove the key with the nearest expire time (minor TTL) # noeviction -> don't expire at all, just return an error on write operations # noeviction -> 不讓任何 key 過期，只是給寫入操作返回一個錯誤 # # Note: with any of the above policies, Redis will return an error on write # operations, when there are not suitable keys for eviction. # # At the date of writing this commands are: set setnx setex append # incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd # sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby # zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby # getset mset msetnx exec sort # # The default is: # # maxmemory-policy noeviction # LRU and minimal TTL algorithms are not precise algorithms but approximated # algorithms (in order to save memory), so you can tune it for speed or # accuracy. For default Redis will check five keys and pick the one that was # used less recently, you can change the sample size using the following # configuration directive. # # The default of 5 produces good enough results. 10 Approximates very closely # true LRU but costs a bit more CPU. 3 is very fast but not very accurate. # # maxmemory-samples 5 ############################## APPEND ONLY MODE ############################### # By default Redis asynchronously dumps the dataset on disk. This mode is # good enough in many applications, but an issue with the Redis process or # a power outage may result into a few minutes of writes lost (depending on # the configured save points). # # The Append Only File is an alternative persistence mode that provides # much better durability. For instance using the default data fsync policy # (see later in the config file) Redis can lose just one second of writes in a # dramatic event like a server power outage, or a single write if something # wrong with the Redis process itself happens, but the operating system is # still running correctly. # # AOF and RDB persistence can be enabled at the same time without problems. # If the AOF is enabled on startup Redis will load the AOF, that is the file # with the better durability guarantees. # # Please check http://redis.io/topics/persistence for more information. appendonly no # The name of the append only file (default: "appendonly.aof") appendfilename "appendonly.aof" # The fsync() call tells the Operating System to actually write data on disk # instead to wait for more data in the output buffer. Some OS will really flush # data on disk, some other OS will just try to do it ASAP. # # Redis supports three different modes: # # no: don't fsync, just let the OS flush the data when it wants. Faster. # always: fsync after every write to the append only log . Slow, Safest. # everysec: fsync only one time every second. Compromise. # # The default is "everysec", as that's usually the right compromise between # speed and data safety. It's up to you to understand if you can relax this to # "no" that will let the operating system flush the output buffer when # it wants, for better performances (but if you can live with the idea of # some data loss consider the default persistence mode that's snapshotting), # or on the contrary, use "always" that's very slow but a bit safer than # everysec. # # More details please check the following article: # http://antirez.com/post/redis-persistence-demystified.html # # If unsure, use "everysec". # appendfsync always appendfsync everysec # appendfsync no # When the AOF fsync policy is set to always or everysec, and a background # saving process (a background save or AOF log background rewriting) is # performing a lot of I/O against the disk, in some Linux configurations # Redis may block too long on the fsync() call. Note that there is no fix for # this currently, as even performing fsync in a different thread will block # our synchronous write(2) call. # # In order to mitigate this problem it's possible to use the following option # that will prevent fsync() from being called in the main process while a # BGSAVE or BGREWRITEAOF is in progress. # # This means that while another child is saving, the durability of Redis is # the same as "appendfsync none". In practical terms, this means that it is # possible to lose up to 30 seconds of log in the worst scenario (with the # default Linux settings). # # If you have latency problems turn this to "yes". Otherwise leave it as # "no" that is the safest pick from the point of view of durability. no-appendfsync-on-rewrite no # Automatic rewrite of the append only file. # Redis is able to automatically rewrite the log file implicitly calling # BGREWRITEAOF when the AOF log size grows by the specified percentage. # # This is how it works: Redis remembers the size of the AOF file after the # latest rewrite (if no rewrite has happened since the restart, the size of # the AOF at startup is used). # # This base size is compared to the current size. If the current size is # bigger than the specified percentage, the rewrite is triggered. Also # you need to specify a minimal size for the AOF file to be rewritten, this # is useful to avoid rewriting the AOF file even if the percentage increase # is reached but it is still pretty small. # # Specify a percentage of zero in order to disable the automatic AOF # rewrite feature. auto-aof-rewrite-percentage 100 auto-aof-rewrite-min-size 64mb ################################ LUA SCRIPTING ############################### # Max execution time of a Lua script in milliseconds. # # If the maximum execution time is reached Redis will log that a script is # still in execution after the maximum allowed time and will start to # reply to queries with an error. # # When a long running script exceed the maximum execution time only the # SCRIPT KILL and SHUTDOWN NOSAVE commands are available. The first can be # used to stop a script that did not yet called write commands. The second # is the only way to shut down the server in the case a write commands was # already issue by the script but the user don't want to wait for the natural # termination of the script. # # Set it to 0 or a negative value for unlimited execution without warnings. lua-time-limit 5000 ################################ REDIS 叢集 ############################### # # 啟用或停用叢集 # cluster-enabled yes # Every cluster node has a cluster configuration file. This file is not # intended to be edited by hand. It is created and updated by Redis nodes. # Every Redis Cluster node requires a different cluster configuration file. # Make sure that instances running in the same system does not have # overlapping cluster configuration file names. # # cluster-config-file nodes-6379.conf # Cluster node timeout is the amount of milliseconds a node must be unreachable # for it to be considered in failure state. # Most other internal time limits are multiple of the node timeout. # # cluster-node-timeout 15000 # A slave of a failing master will avoid to start a failover if its data # looks too old. # # There is no simple way for a slave to actually have a exact measure of # its "data age", so the following two checks are performed: # # 1) If there are multiple slaves able to failover, they exchange messages # in order to try to give an advantage to the slave with the best # replication offset (more data from the master processed). # Slaves will try to get their rank by offset, and apply to the start # of the failover a delay proportional to their rank. # # 2) Every single slave computes the time of the last interaction with # its master. This can be the last ping or command received (if the master # is still in the "connected" state), or the time that elapsed since the # disconnection with the master (if the replication link is currently down). # If the last interaction is too old, the slave will not try to failover # at all. # # The point "2" can be tuned by user. Specifically a slave will not perform # the failover if, since the last interaction with the master, the time # elapsed is greater than: # # (node-timeout * slave-validity-factor) + repl-ping-slave-period # # So for example if node-timeout is 30 seconds, and the slave-validity-factor # is 10, and assuming a default repl-ping-slave-period of 10 seconds, the # slave will not try to failover if it was not able to talk with the master # for longer than 310 seconds. # # A large slave-validity-factor may allow slaves with too old data to failover # a master, while a too small value may prevent the cluster from being able to # elect a slave at all. # # For maximum availability, it is possible to set the slave-validity-factor # to a value of 0, which means, that slaves will always try to failover the # master regardless of the last time they interacted with the master. # (However they'll always try to apply a delay proportional to their # offset rank). # # Zero is the only value able to guarantee that when all the partitions heal # the cluster will always be able to continue. # # cluster-slave-validity-factor 10 # Cluster slaves are able to migrate to orphaned masters, that are masters # that are left without working slaves. This improves the cluster ability # to resist to failures as otherwise an orphaned master can't be failed over # in case of failure if it has no working slaves. # # Slaves migrate to orphaned masters only if there are still at least a # given number of other working slaves for their old master. This number # is the "migration barrier". A migration barrier of 1 means that a slave # will migrate only if there is at least 1 other working slave for its master # and so forth. It usually reflects the number of slaves you want for every # master in your cluster. # # Default is 1 (slaves migrate only if their masters remain with at least # one slave). To disable migration just set it to a very large value. # A value of 0 can be set but is useful only for debugging and dangerous # in production. # # cluster-migration-barrier 1 # In order to setup your cluster make sure to read the documentation # available at http://redis.io web site. ################################## SLOW LOG ################################### # The Redis Slow Log is a system to log queries that exceeded a specified # execution time. The execution time does not include the I/O operations # like talking with the client, sending the reply and so forth, # but just the time needed to actually execute the command (this is the only # stage of command execution where the thread is blocked and can not serve # other requests in the meantime). # # You can configure the slow log with two parameters: one tells Redis # what is the execution time, in microseconds, to exceed in order for the # command to get logged, and the other parameter is the length of the # slow log. When a new command is logged the oldest one is removed from the # queue of logged commands. # The following time is expressed in microseconds, so 1000000 is equivalent # to one second. Note that a negative number disables the slow log, while # a value of zero forces the logging of every command. slowlog-log-slower-than 10000 # There is no limit to this length. Just be aware that it will consume memory. # You can reclaim memory used by the slow log with SLOWLOG RESET. slowlog-max-len 128 ############################# Event notification ############################## # Redis can notify Pub/Sub clients about events happening in the key space. # This feature is documented at http://redis.io/topics/keyspace-events # # For instance if keyspace events notification is enabled, and a client # performs a DEL operation on key "foo" stored in the Database 0, two # messages will be published via Pub/Sub: # # PUBLISH

[email protected]__:foo del # PUBLISH [email protected]__:del foo # # It is possible to select the events that Redis will notify among a set # of classes. Every class is identified by a single character: # # K Keyspace events, published with [email protected]<db>__ prefix. # E Keyevent events, published with

[email protected]<db>__ prefix. # g Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ... # $ String commands # l List commands # s Set commands # h Hash commands # z Sorted set commands # x Expired events (events generated every time a key expires) # e Evicted events (events generated when a key is evicted for maxmemory) # A Alias for g$lshzxe, so that the "AKE" string means all the events. # # The "notify-keyspace-events" takes as argument a string that is composed # by zero or multiple characters. The empty string means that notifications # are disabled at all. # # Example: to enable list and generic events, from the point of view of the # event name, use: # # notify-keyspace-events Elg # # Example 2: to get the stream of the expired keys subscribing to channel # name

[email protected]__:expired use: # # notify-keyspace-events Ex # # By default all notifications are disabled because most users don't need # this feature and the feature has some overhead. Note that if you don't # specify at least one of K or E, no events will be delivered. notify-keyspace-events "" ############################### ADVANCED CONFIG ############################### # Hashes are encoded using a memory efficient data structure when they have a # small number of entries, and the biggest entry does not exceed a given # threshold. These thresholds can be configured using the following directives. hash-max-ziplist-entries 512 hash-max-ziplist-value 64 # Similarly to hashes, small lists are also encoded in a special way in order # to save a lot of space. The special representation is only used when # you are under the following limits: list-max-ziplist-entries 512 list-max-ziplist-value 64 # Sets have a special encoding in just one case: when a set is composed # of just strings that happens to be integers in radix 10 in the range # of 64 bit signed integers. # The following configuration setting sets the limit in the size of the # set in order to use this special memory saving encoding. set-max-intset-entries 512 # Similarly to hashes and lists, sorted sets are also specially encoded in # order to save a lot of space. This encoding is only used when the length and # elements of a sorted set are below the following limits: zset-max-ziplist-entries 128 zset-max-ziplist-value 64 # HyperLogLog sparse representation bytes limit. The limit includes the # 16 bytes header. When an HyperLogLog using the sparse representation crosses # this limit, it is converted into the dense representation. # # A value greater than 16000 is totally useless, since at that point the # dense representation is more memory efficient. # # The suggested value is ~ 3000 in order to have the benefits of # the space efficient encoding without slowing down too much PFADD, # which is O(N) with the sparse encoding. The value can be raised to # ~ 10000 when CPU is not a concern, but space is, and the data set is # composed of many HyperLogLogs with cardinality in the 0 - 15000 range. hll-sparse-max-bytes 3000 # Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in # order to help rehashing the main Redis hash table (the one mapping top-level # keys to values). The hash table implementation Redis uses (see dict.c) # performs a lazy rehashing: the more operation you run into a hash table # that is rehashing, the more rehashing "steps" are performed, so if the # server is idle the rehashing is never complete and some more memory is used # by the hash table. # # The default is to use this millisecond 10 times every second in order to # active rehashing the main dictionaries, freeing memory when possible. # # If unsure: # use "activerehashing no" if you have hard latency requirements and it is # not a good thing in your environment that Redis can reply form time to time # to queries with 2 milliseconds delay. # # use "activerehashing yes" if you don't have such hard requirements but # want to free memory asap when possible. activerehashing yes # The client output buffer limits can be used to force disconnection of clients # that are not reading data from the server fast enough for some reason (a # common reason is that a Pub/Sub client can't consume messages as fast as the # publisher can produce them). # # The limit can be set differently for the three different classes of clients: # # normal -> normal clients # slave -> slave clients and MONITOR clients # pubsub -> clients subscribed to at least one pubsub channel or pattern # # The syntax of every client-output-buffer-limit directive is the following: # # client-output-buffer-limit <class> <hard limit> <soft limit> <soft seconds> # # A client is immediately disconnected once the hard limit is reached, or if # the soft limit is reached and remains reached for the specified number of # seconds (continuously). # So for instance if the hard limit is 32 megabytes and the soft limit is # 16 megabytes / 10 seconds, the client will get disconnected immediately # if the size of the output buffers reach 32 megabytes, but will also get # disconnected if the client reaches 16 megabytes and continuously overcomes # the limit for 10 seconds. # # By default normal clients are not limited because they don't receive data # without asking (in a push way), but just after a request, so only # asynchronous clients may create a scenario where data is requested faster # than it can read. # # Instead there is a default limit for pubsub and slave clients, since # subscribers and slaves receive data in a push fashion. # # Both the hard or the soft limit can be disabled by setting them to zero. client-output-buffer-limit normal 0 0 0 client-output-buffer-limit slave 256mb 64mb 60 client-output-buffer-limit pubsub 32mb 8mb 60 # Redis calls an internal function to perform many background tasks, like # closing connections of clients in timeout, purging expired keys that are # never requested, and so forth. # # Not all tasks are performed with the same frequency, but Redis checks for # tasks to perform accordingly to the specified "hz" value. # # By default "hz" is set to 10. Raising the value will use more CPU when # Redis is idle, but at the same time will make Redis more responsive when # there are many keys expiring at the same time, and timeouts may be # handled with more precision. # # The range is between 1 and 500, however a value over 100 is usually not # a good idea. Most users should use the default of 10 and raise this up to # 100 only in environments where very low latency is required. hz 10 # When a child rewrites the AOF file, if the following option is enabled # the file will be fsync-ed every 32 MB of data generated. This is useful # in order to commit the file to the disk more incrementally and avoid # big latency spikes. aof-rewrite-incremental-fsync yes