# Redis configuration file example.
################################## INCLUDES ###################################
# Include one or more other config files here. This is useful if you # have a standard template that goes to all Redis servers but also need # to customize a few per-server settings. Include files can include # other files, so use this wisely. # # Notice option "include" won't be rewritten by command "CONFIG REWRITE" # from admin or Redis Sentinel. Since Redis always uses the last processed # line as value of a configuration directive, you'd better put includes # at the beginning of this file to avoid overwriting config change at runtime. # # If instead you are interested in using includes to override configuration # options, it is better to use include as the last line. # # 假如說你有一個可用於全部的 redis server 的標準配置模板, # 但針對某些 server 又須要一些個性化的設置, # 你可使用 include 來包含一些其餘的配置文件,這對你來講是很是有用的。 # # 可是要注意哦,include 是不能被 config rewrite 命令改寫的 # 因爲 redis 老是以最後的加工線做爲一個配置指令值,因此你最好是把 include 放在這個文件的最前面, # 以免在運行時覆蓋配置的改變,相反,你就把它放在後面 # include /path/to/local.conf # include /path/to/other.conf
################################ GENERAL #####################################
# By default Redis does not run as a daemon. Use 'yes' if you need it. # Note that Redis will write a pid file in /var/run/redis.pid when daemonized. # 默認狀況下 redis 不是做爲守護進程運行的,若是你想讓它在後臺運行,你就把它改爲 yes。 # 當redis做爲守護進程運行的時候,它會寫一個 pid 到 /var/run/redis.pid 文件裏面。 daemonize yes # When running daemonized, Redis writes a pid file in /var/run/redis.pid by # default. You can specify a custom pid file location here. # 當 Redis 以守護進程的方式運行的時候,Redis 默認會把 pid 文件放在/var/run/redis.pid # 可配置到其餘地址,當運行多個 redis 服務時,須要指定不一樣的 pid 文件和端口 # 指定存儲Redis進程號的文件路徑 pidfile /usr/local/redis/redis.pid
# Accept connections on the specified port, default is 6379. # If port 0 is specified Redis will not listen on a TCP socket. # 端口,默認端口是6379,生產環境中建議更改端口號,安全性更高 # 若是你設爲 0 ,redis 將不在 socket 上監放任何客戶端鏈接。 port 6379
# TCP listen() backlog. # # In high requests-per-second environments you need an high backlog in order # to avoid slow clients connections issues. Note that the Linux kernel # will silently truncate it to the value of /proc/sys/net/core/somaxconn so # make sure to raise both the value of somaxconn and tcp_max_syn_backlog # in order to get the desired effect. # TCP 監聽的最大容納數量 # 此參數肯定了TCP鏈接中已完成隊列(完成三次握手以後)的長度, # 當系統併發量大而且客戶端速度緩慢的時候,你須要把這個值調高以免客戶端鏈接緩慢的問題。 # Linux 內核會一言不發的把這個值縮小成 /proc/sys/net/core/somaxconn 對應的值128,默認是511,而Linux的默認參數值是128,因此能夠將這二個參數一塊兒參考設定,你以便達到你的預期。 # 實際在啓動redis時,會有WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128. tcp-backlog 511
# By default Redis listens for connections from all the network interfaces # available on the server. It is possible to listen to just one or multiple # interfaces using the "bind" configuration directive, followed by one or # more IP addresses. # # Examples: # # bind 192.168.1.100 10.0.0.1 # 有時候爲了安全起見,redis通常都是監聽127.0.0.1 可是有時候又有同網段能鏈接的需求,固然能夠綁定0.0.0.0 用iptables來控制訪問權限,或者設置redis訪問密碼來保證數據安全 # 不設置將處理全部請求,建議生產環境中設置,有個誤區:bind是用來限制外網IP訪問的,其實不是,限制外網ip訪問能夠經過iptables;
如:-A INPUT -s 10.10.1.0/24 -p tcp -m state --state NEW -m tcp --dport 9966 -j ACCEPT ; # 實際上,bind ip 綁定的是redis所在服務器網卡的ip,固然127.0.0.1也是能夠的 #若是綁定一個外網ip,就會報錯:Creating Server TCP listening socket xxx.xxx.xxx.xxx:6379: bind: Cannot assign requested address # bind 127.0.0.1 bind 127.0.0.1 10.10.1.3 # 假設綁定是以上ip,使用 netstat -anp|grep 9966 會發現,這兩個ip被bind,其中10.10.1.3是服務器網卡的ip # tcp 0 0 10.10.1.3:6379 0.0.0.0:* LISTEN 11188/redis-server # tcp 0 0 127.0.0.1:6379 0.0.0.0:* LISTEN 11188/redis-server
# Specify the path for the Unix socket that will be used to listen for # incoming connections. There is no default, so Redis will not listen # on a unix socket when not specified. # # unixsocket /tmp/redis.sock # unixsocketperm 700 # Close the connection after a client is idle for N seconds (0 to disable)
#前段時間,因爲線上redis服務器的內存使用率達到了機器總內存的50%以上,致使內存數據的dump持久化一直失敗。擴展到多臺redis後,應用系統訪問redis時,
#在業務量較少時,時不時會出現如下異常,當業務量較大,redis訪問頻率很高時,卻不會發生這個異常,一時以爲很詭異
#redis.clients.jedis.exceptions.JedisConnectionException:It seems like server has closed the connection.
#看提示,應該是服務端主動關閉了鏈接。查看了新上線的redis服務器的配置,有這麼一項:timeout 120
#客戶端和Redis服務端的鏈接超時時間,默認是0,表示服務端永不主動關閉鏈接。
#而op人員把服務器端的超時時間設置爲了120秒。這就解釋了發生這個異常的緣由。客戶端使用了一個鏈接池管理訪問redis的全部鏈接,這些鏈接是長鏈接,當業務量較小時,
#客戶端部分鏈接使用率較低,當兩次使用之間的間隔超過120秒時,redis服務端就主動關閉了這個鏈接,而等客戶端下次再使用這個鏈接對象時,發現服務端已經關閉了鏈接,進而報錯。
#解決方案有兩種:
1. 在redis-cli下直接修改redis 的配置,把timeout改回爲0,無需重啓redis便可直接生效。html
2. 修改應用系統代碼,設置鏈接的最大空閒時長(超出此時長將斷開空閒鏈接)小於120秒。node
出於改動成本考慮,採用了第一種方案,修改後,報錯再也不出現。linux
timeout 0
# TCP keepalive. # # If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence # of communication. This is useful for two reasons: # # 1) Detect dead peers. # 2) Take the connection alive from the point of view of network # equipment in the middle. # # On Linux, the specified value (in seconds) is the period used to send ACKs. # Note that to close the connection the double of the time is needed. # On other kernels the period depends on the kernel configuration. # # A reasonable value for this option is 60 seconds. # tcp 心跳包。 # # 若是設置爲非零,則在與客戶端缺少通信的時候使用 SO_KEEPALIVE 發送 tcp acks 給客戶端。 # 這個之全部有用,主要由兩個緣由: # # 1) 防止死的 peers # 2) Take the connection alive from the point of view of network # equipment in the middle. # # 推薦一個合理的值就是60秒 tcp-keepalive 60
# Specify the server verbosity level. # This can be one of: # debug (a lot of information, useful for development/testing) # verbose (many rarely useful info, but not a mess like the debug level) # notice (moderately verbose, what you want in production probably) # warning (only very important / critical messages are logged) # 日誌記錄等級,4個可選值debug,verbose,notice,warning # 能夠是下面的這些值: # 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 (僅僅一些重要的消息被記錄) loglevel notice
# Specify the log file name. Also the empty string can be used to force # Redis to log on the standard output. Note that if you use standard # output for logging but daemonize, logs will be sent to /dev/null #配置 log 文件地址,默認打印在命令行終端的窗口上,也可設爲/dev/null屏蔽日誌。該地址若是配置的是相對路徑,相對於dir配置的路徑.通常推薦配置絕對路徑 logfile "./redis6379.log"
# To enable logging to the system logger, just set 'syslog-enabled' to yes, # and optionally update the other syslog parameters to suit your needs. # 要想把日誌記錄到系統日誌,就把它改爲 yes, # 也能夠可選擇性的更新其餘的syslog 參數以達到你的要求 # syslog-enabled no
# Specify the syslog identity. # 設置 syslog 的 identity。 # syslog-ident redis # Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7. # syslog-facility local0 # Set the number of databases. The default database is DB 0, you can select # a different one on a per-connection basis using SELECT <dbid> where # dbid is a number between 0 and 'databases'-1 # 可用的數據庫數,默認值爲16,默認數據庫爲0,數據庫範圍在0-(database-1)之間 databases 16
################################ SNAPSHOTTING ################################
# Save the DB on disk: # # save <seconds> <changes> # # Will save the DB if both the given number of seconds and the given # number of write operations against the DB occurred. # # In the example below the behaviour will be to save: # after 900 sec (15 min) if at least 1 key changed # after 300 sec (5 min) if at least 10 keys changed # after 60 sec if at least 10000 keys changed # # Note: you can disable saving completely by commenting out all "save" lines. # # It is also possible to remove all the previously configured save # points by adding a save directive with a single empty string argument # like in the following example: # # save "" # 在 900 秒內最少有 1 個 key 被改動,或者 300 秒內最少有 10 個 key 被改動,又或者 60 秒內最少有 1000 個 key 被改動,以上三個條件隨便知足一個,就觸發一次保存操做。 # if(在60秒以內有10000個keys發生變化時){ # 進行鏡像備份 # }else if(在300秒以內有10個keys發生了變化){ # 進行鏡像備份 # }else if(在900秒以內有1個keys發生了變化){ # 進行鏡像備份 # } save 900 1 save 300 10 save 60 10000
# By default Redis will stop accepting writes if RDB snapshots are enabled # (at least one save point) and the latest background save failed. # This will make the user aware (in a hard way) that data is not persisting # on disk properly, otherwise chances are that no one will notice and some #:/ disaster will happen. # # If the background saving process will start working again Redis will # automatically allow writes again. # # However if you have setup your proper monitoring of the Redis server # and persistence, you may want to disable this feature so that Redis will # continue to work as usual even if there are problems with disk, # permissions, and so forth. # 默認狀況下,若是 redis 最後一次的後臺保存失敗,redis 將中止接受寫操做, # 這樣以一種強硬的方式讓用戶知道數據不能正確的持久化到磁盤, # 不然就會沒人注意到災難的發生。 # # 若是後臺保存進程從新啓動工做了,redis 也將自動的容許寫操做。 # # 然而你要是安裝了靠譜的監控,你可能不但願 redis 這樣作,那你就改爲 no 好 stop-writes-on-bgsave-error yes
# Compress string objects using LZF when dump .rdb databases? # For default that's set to 'yes' as it's almost always a win. # If you want to save some CPU in the saving child set it to 'no' but # the dataset will likely be bigger if you have compressible values or keys. # 在進行備份時,是否進行壓縮 # 是否在 dump .rdb 數據庫的時候使用 LZF 壓縮字符串 # 默認都設爲 yes # 若是你但願保存子進程節省點 cpu ,你就設置它爲 no , # 不過這個數據集可能就會比較大 rdbcompression yes
# Since version 5 of RDB a CRC64 checksum is placed at the end of the file. # This makes the format more resistant to corruption but there is a performance # hit to pay (around 10%) when saving and loading RDB files, so you can disable it # for maximum performances. # # RDB files created with checksum disabled have a checksum of zero that will # tell the loading code to skip the check. # 讀取和寫入的時候是否支持CRC64校驗,默認是開啓的 rdbchecksum yes # The filename where to dump the DB # 備份文件的文件名 dbfilename dump.rdb
# The working directory. # # The DB will be written inside this directory, with the filename specified # above using the 'dbfilename' configuration directive. # # The Append Only File will also be created inside this directory. # # Note that you must specify a directory here, not a file name. # 數據庫備份的文件放置的路徑 # 路徑跟文件名分開配置是由於 Redis 備份時,先會將當前數據庫的狀態寫入到一個臨時文件 # 等備份完成時,再把該臨時文件替換爲上面所指定的文件 # 而臨時文件和上面所配置的備份文件都會放在這個指定的路徑當中 # 默認值爲 ./,該相對路徑是根據你啓動redis-server的路徑有關,好比./src/redis-server,那麼./就表明和src同級目錄,最好用絕對路徑。 dir /usr/local/redis/data6379
################################# REPLICATION - 主從複製 #################################
# Master-Slave replication. Use slaveof to make a Redis instance a copy of # another Redis server. A few things to understand ASAP about Redis replication. # # 1) Redis replication is asynchronous, but you can configure a master to # stop accepting writes if it appears to be not connected with at least # a given number of slaves. # 2) Redis slaves are able to perform a partial resynchronization with the # master if the replication link is lost for a relatively small amount of # time. You may want to configure the replication backlog size (see the next # sections of this file) with a sensible value depending on your needs. # 3) Replication is automatic and does not need user intervention. After a # network partition slaves automatically try to reconnect to masters # and resynchronize with them. # # 設置該數據庫爲其餘數據庫的從數據庫 # slaveof <masterip> <masterport> 當本機爲從服務時,設置主服務的IP及端口 # slaveof <masterip> <masterport>
# If the master is password protected (using the "requirepass" configuration # directive below) it is possible to tell the slave to authenticate before # starting the replication synchronization process, otherwise the master will # refuse the slave request. # # 指定與主數據庫鏈接時須要的密碼驗證 # masterauth <master-password> 當本機爲從服務時,設置訪問master服務器的密碼 # masterauth <master-password>
# When a slave loses its connection with the master, or when the replication # is still in progress, the slave can act in two different ways: # # 1) if slave-serve-stale-data is set to 'yes' (the default) the slave will # still reply to client requests, possibly with out of date data, or the # data set may just be empty if this is the first synchronization. # # 2) if slave-serve-stale-data is set to 'no' the slave will reply with # an error "SYNC with master in progress" to all the kind of commands # but to INFO and SLAVEOF. # # 當slave服務器和master服務器失去鏈接後,或者當數據正在複製傳輸的時候,若是此參數值設置「yes」,slave服務器能夠繼續接受客戶端的請求,不然,
#會返回給請求的客戶端以下信息「SYNC with master in progress」,除了INFO,SLAVEOF這兩個命令 slave-serve-stale-data yes
# You can configure a slave instance to accept writes or not. Writing against # a slave instance may be useful to store some ephemeral data (because data # written on a slave will be easily deleted after resync with the master) but # may also cause problems if clients are writing to it because of a # misconfiguration. # # Since Redis 2.6 by default slaves are read-only. # # Note: read only slaves are not designed to be exposed to untrusted clients # on the internet. It's just a protection layer against misuse of the instance. # Still a read only slave exports by default all the administrative commands # such as CONFIG, DEBUG, and so forth. To a limited extent you can improve # security of read only slaves using 'rename-command' to shadow all the # administrative / dangerous commands. # 是否容許slave服務器節點只提供讀服務 slave-read-only yes
# Slaves send PINGs to server in a predefined interval. It's possible to change # this interval with the repl_ping_slave_period option. The default value is 10 # seconds. # # Slaves 在一個預約義的時間間隔內發送 ping 命令到 server 。 # 你能夠改變這個時間間隔。默認爲 10 秒。 # repl-ping-slave-period 10
# The following option sets the replication timeout for: # # 1) Bulk transfer I/O during SYNC, from the point of view of slave. # 2) Master timeout from the point of view of slaves (data, pings). # 3) Slave timeout from the point of view of masters (REPLCONF ACK pings). # # It is important to make sure that this value is greater than the value # specified for repl-ping-slave-period otherwise a timeout will be detected # every time there is low traffic between the master and the slave. # # 設置主從複製過時時間 # 這個值必定要比 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. # 指定向slave同步數據時,是否禁用socket的NO_DELAY選 項。若配置爲「yes」,則禁用NO_DELAY,則TCP協議棧會合並小包統一發送,這樣能夠減小主從節點間的包數量並節省帶寬,但會增長數據同步到 slave的時間。
#若配置爲「no」,代表啓用NO_DELAY,則TCP協議棧不會延遲小包的發送時機,這樣數據同步的延時會減小,但須要更大的帶寬。 一般狀況下,應該配置爲no以下降同步延時,但在主從節點間網絡負載已經很高的狀況下,能夠配置爲yes。
repl-disable-tcp-nodelay no
# Set the replication backlog size. The backlog is a buffer that accumulates # slave data when slaves are disconnected for some time, so that when a slave # wants to reconnect again, often a full resync is not needed, but a partial # resync is enough, just passing the portion of data the slave missed while # disconnected. # # The bigger the replication backlog, the longer the time the slave can be # disconnected and later be able to perform a partial resynchronization. # # The backlog is only allocated once there is at least a slave connected. # # 設置主從複製容量大小。這個 backlog 是一個用來在 slaves 被斷開鏈接時 # 存放 slave 數據的 buffer,因此當一個 slave 想要從新鏈接,一般不但願所有從新同步, # 只是部分同步就夠了,僅僅傳遞 slave 在斷開鏈接時丟失的這部分數據。
# 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 能夠斷開鏈接的時間就越長。
# repl-backlog-size 1mb
# After a master has no longer connected slaves for some time, the backlog # will be freed. The following option configures the amount of seconds that # need to elapse, starting from the time the last slave disconnected, for # the backlog buffer to be freed. # # A value of 0 means to never release the backlog. # # 在某些時候,master 再也不鏈接 slaves,backlog 將被釋放。 # 若是設置爲 0 ,意味着毫不釋放 backlog 。 # repl-backlog-ttl 3600
# The slave priority is an integer number published by Redis in the INFO output. # It is used by Redis Sentinel in order to select a slave to promote into a # master if the master is no longer working correctly. # # A slave with a low priority number is considered better for promotion, so # for instance if there are three slaves with priority 10, 100, 25 Sentinel will # pick the one with priority 10, that is the lowest. # # However a special priority of 0 marks the slave as not able to perform the # role of master, so a slave with priority of 0 will never be selected by # Redis Sentinel for promotion. # # By default the priority is 100. # 指定slave的優先級。在不僅1個slave存在的部署環境下,當master宕機時,Redis # Sentinel會將priority值最小的slave提高爲master。 # 這個值越小,就越會被優先選中,須要注意的是, # 若該配置項爲0,則對應的slave永遠不會自動提高爲master。 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 GUARANTEE 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.
################################## SECURITY ###################################
# Require clients to issue AUTH <PASSWORD> before processing any other # commands. This might be useful in environments in which you do not trust # others with access to the host running redis-server. # # This should stay commented out for backward compatibility and because most # people do not need auth (e.g. they run their own servers). # # Warning: since Redis is pretty fast an outside user can try up to # 150k passwords per second against a good box. This means that you should # use a very strong password otherwise it will be very easy to break. # # 設置鏈接redis的密碼 # redis速度至關快,一個外部用戶在一秒鐘進行150K次密碼嘗試,需指定強大的密碼來防止暴力破解 requirepass set_enough_strong_passwd # 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. # 重命名一些高危命令,用來禁止高危命令 rename-command FLUSHALL ZYzv6FOBdwflW2nX rename-command CONFIG aI7zwm1GDzMMrEi rename-command EVAL S9UHPKEpSvUJMM rename-command FLUSHDB D60FPVDJuip7gy6l
################################### LIMITS ####################################
# Set the max number of connected clients at the same time. By default # this limit is set to 10000 clients, however if the Redis server is not # able to configure the process file limit to allow for the specified limit # the max number of allowed clients is set to the current file limit # minus 32 (as Redis reserves a few file descriptors for internal uses). # # Once the limit is reached Redis will close all the new connections sending # an error 'max number of clients reached'. # # 限制同時鏈接的客戶數量,默認是10000 # 當鏈接數超過這個值時,redis 將再也不接收其餘鏈接請求,客戶端嘗試鏈接時將收到 error 信息 # maxclients 10000
# Don't use more memory than the specified amount of bytes. # When the memory limit is reached Redis will try to remove keys # according to the eviction policy selected (see maxmemory-policy). # # If Redis can't remove keys according to the policy, or if the policy is # set to 'noeviction', Redis will start to reply with errors to commands # that would use more memory, like SET, LPUSH, and so on, and will continue # to reply to read-only commands like GET. # # This option is usually useful when using Redis as an LRU cache, or to set # a hard memory limit for an instance (using the 'noeviction' policy). # # WARNING: If you have slaves attached to an instance with maxmemory on, # the size of the output buffers needed to feed the slaves are subtracted # from the used memory count, so that network problems / resyncs will # not trigger a loop where keys are evicted, and in turn the output # buffer of slaves is full with DELs of keys evicted triggering the deletion # of more keys, and so forth until the database is completely emptied. # # In short... if you have slaves attached it is suggested that you set a lower # limit for maxmemory so that there is some free RAM on the system for slave # output buffers (but this is not needed if the policy is 'noeviction'). # # 設置redis可以使用的最大內存。 # 達到最大內存設置後,Redis會先嚐試清除已到期或即將到期的Key(設置過expire信息的key) # 在刪除時,按照過時時間進行刪除,最先將要被過時的key將最早被刪除 # 若是已到期或即將到期的key刪光,仍進行set操做,那麼將返回錯誤 # 此時redis將再也不接收寫請求,只接收get請求。 # maxmemory的設置比較適合於把redis看成於相似memcached 的緩存來使用 # maxmemory <bytes>
# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory # is reached. You can select among five behaviors: # # volatile-lru -> remove the key with an expire set using an LRU algorithm # allkeys-lru -> remove any key according to the LRU algorithm # volatile-random -> remove a random key with an expire set # allkeys-random -> remove a random key, any key # volatile-ttl -> remove the key with the nearest expire time (minor TTL) # noeviction -> don't expire at all, just return an error on write operations # # Note: with any of the above policies, Redis will return an error on write # operations, when there are no suitable keys for eviction. # # At the date of writing these 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.
# redis 默認每次更新操做後會在後臺異步的把數據庫鏡像備份到磁盤,但該備份很是耗時,且備份不宜太頻繁 # redis 同步數據文件是按上面save條件來同步的 # 若是發生諸如拉閘限電、拔插頭等情況,那麼將形成比較大範圍的數據丟失 # 因此redis提供了另一種更加高效的數據庫備份及災難恢復方式 # 開啓append only 模式後,redis 將每一次寫操做請求都追加到appendonly.aof 文件中 # redis從新啓動時,會從該文件恢復出以前的狀態。 # 但可能會形成 appendonly.aof 文件過大,因此redis支持BGREWRITEAOF 指令,對appendonly.aof從新整理,默認是不開啓的。 appendonly no
# The name of the append only file (default: "appendonly.aof") # 默認爲appendonly.aof。 appendfilename "appendonly.aof"
# The fsync() call tells the Operating System to actually write data on disk # instead of waiting 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".
# 設置對 appendonly.aof 文件進行同步的頻率,有三種選擇always、everysec、no,默認是everysec表示每秒同步一次。 # always 表示每次有寫操做都進行同步,everysec 表示對寫操做進行累積,每秒同步一次。 # no表示等操做系統進行數據緩存同步到磁盤,都進行同步,everysec 表示對寫操做進行累積,每秒同步一次 # 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. # 指定是否在後臺aof文件rewrite期間調用fsync,默認爲no,表示要調用fsync(不管後臺是否有子進程在刷盤)。Redis在後臺寫RDB文件或重寫afo文件期間會存在大量磁盤IO,此時,在某些linux系統中,調用fsync可能會阻塞。 no-appendfsync-on-rewrite yes
# 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. # 指定Redis重寫aof文件的條件,默認爲100,表示與上次rewrite的aof文件大小相比,當前aof文件增加量超過上次afo文件大小的100%時,就會觸發background rewrite。若配置爲0,則會禁用自動rewrite auto-aof-rewrite-percentage 100 # 指定觸發rewrite的aof文件大小。若aof文件小於該值,即便當前文件的增量比例達到auto-aof-rewrite-percentage的配置值,也不會觸發自動rewrite。即這兩個配置項同時知足時,纔會觸發rewrite。 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 exceeds 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 command was # already issued by the script but the user doesn't want to wait for the natural # termination of the script. # # Set it to 0 or a negative value for unlimited execution without warnings. # 一個Lua腳本最長的執行時間,單位爲毫秒,若是爲0或負數表示無限執行時間,默認爲5000 lua-time-limit 5000
############################### 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. # 當hash中包含超過指定元素個數而且最大的元素沒有超過臨界時, # hash將以一種特殊的編碼方式(大大減小內存使用)來存儲,這裏能夠設置這兩個臨界值 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數據類型多少節點如下會採用去指針的緊湊存儲格式。 # list數據類型節點值大小小於多少字節會採用緊湊存儲格式。 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 happen 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數據類型內部數據若是所有是數值型,且包含多少節點如下會採用緊湊格式存儲。 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: # zsort數據類型多少節點如下會採用去指針的緊湊存儲格式。 # zsort數據類型節點值大小小於多少字節會採用緊湊存儲格式。 zset-max-ziplist-entries 128 zset-max-ziplist-value 64
# 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 # actively rehash 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 from 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. # Redis將在每100毫秒時使用1毫秒的CPU時間來對redis的hash表進行從新hash,能夠下降內存的使用 # 當你的使用場景中,有很是嚴格的實時性須要,不可以接受Redis時不時的對請求有2毫秒的延遲的話,把這項配置爲no。 # 若是沒有這麼嚴格的實時性要求,能夠設置爲yes,以便可以儘量快的釋放內存 activerehashing yes
# 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過程當中,是否採起增量文件同步策略,默認爲「yes」。 rewrite過程當中,每32M數據進行一次文件同步,這樣能夠減小aof大文件寫入對磁盤的操做次數 aof-rewrite-incremental-fsync yes
# redis數據存儲 redis的存儲分爲內存存儲、磁盤存儲和log文件三部分,配置文件中有三個參數對其進行配置。 save seconds updates,save配置,指出在多長時間內,有多少次更新操做,就將數據同步到數據文件。可多個條件配合,默認配置了三個條件。 appendonly yes/no ,appendonly配置,指出是否在每次更新操做後進行日誌記錄,若是不開啓,可能會在斷電時致使一段時間內的數據丟失。由於redis自己同步數據文件是按上面的save條件來同步的,因此有的數據會在一段時間內只存在於內存中。 appendfsync no/always/everysec ,appendfsync配置,no表示等操做系統進行數據緩存同步到磁盤,always表示每次更新操做後手動調用fsync()將數據寫到磁盤,everysec表示每秒同步一次。