一. Redis安裝和連接
1. 下載地址
官網：https://redis.io/
官網-中文：http://www.redis.cn/
Linux下載地址：https://download.redis.io/releases/
Windows下載地址：https://github.com/MicrosoftArchive/redis/tags
2. Linux中安裝
基於Centos8 安裝 Redis 5.0 詳見：https://www.cnblogs.com/yaopengfei/p/13766324.html
3. docker中安裝
基於docker安裝Redis5.0 或者最新版本 詳見：https://www.cnblogs.com/yaopengfei/p/13630267.html
4. windows中安裝
直接雙擊：redis-server.exe 程序，就可以啟動Server端。
PS. 指令連接寫法：
--win下的連接 redis-cli.exe -h 192.168.137.201 -p 6379 --Linux下連接（多了 ./ 表示當前目錄） ./redis-cli.exe -h 192.168.137.201 -p 6379 --含密碼 ./redis-cli.exe -h 192.168.137.201 -p 6379 -a 123456 --集群的連接方式(加 -c) ./redis-cli -c -h 192.168.137.201 -p 6380 -a 123456
二. 目錄配置詳解
1. Redis目錄說明
以上為Redis5.0的安裝目錄下的文件。
(1). redis-benchmark：測試Redis性能的工具，可以同時模擬n個客戶發送請求。
(2). redis-check-aof：aof文件校驗、修復。
(3). redis-check-rdb：rdb文件校驗、修復。
(4). redis-cli：redis客戶端
(5). redis.conf：redis配置文件
(6). redis-sentinel：redis哨兵
(7). redis-server：redis服務端
2. 配置文件詳解
以Redis5.0為例介紹配置文件，默認配置文件如下：
# Redis configuration file example. # # Note that in order to read the configuration file, Redis must be # started with the file path as first argument: # # ./redis-server /path/to/redis.conf # Note on units: when memory size is needed, it is possible to specify # it in the usual form of 1k 5GB 4M and so forth: # # 1k => 1000 bytes # 1kb => 1024 bytes # 1m => 1000000 bytes # 1mb => 1024*1024 bytes # 1g => 1000000000 bytes # 1gb => 1024*1024*1024 bytes # # units are case insensitive so 1GB 1Gb 1gB are all the same. ################################## 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. # # include /path/to/local.conf # include /path/to/other.conf ################################## MODULES ##################################### # Load modules at startup. If the server is not able to load modules # it will abort. It is possible to use multiple loadmodule directives. # # loadmodule /path/to/my_module.so # loadmodule /path/to/other_module.so ################################## NETWORK ##################################### # By default, if no "bind" configuration directive is specified, Redis listens # for connections from all the network interfaces available on the server. # It is possible to listen to just one or multiple selected interfaces using # the "bind" configuration directive, followed by one or more IP addresses. # # Examples: # # bind 192.168.1.100 10.0.0.1 # bind 127.0.0.1 ::1 # # ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the # internet, binding to all the interfaces is dangerous and will expose the # instance to everybody on the internet. So by default we uncomment the # following bind directive, that will force Redis to listen only into # the IPv4 loopback interface address (this means Redis will be able to # accept connections only from clients running into the same computer it # is running). # # IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES # JUST COMMENT THE FOLLOWING LINE. # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ bind 127.0.0.1 # Protected mode is a layer of security protection, in order to avoid that # Redis instances left open on the internet are accessed and exploited. # # When protected mode is on and if: # # 1) The server is not binding explicitly to a set of addresses using the # "bind" directive. # 2) No password is configured. # # The server only accepts connections from clients connecting from the # IPv4 and IPv6 loopback addresses 127.0.0.1 and ::1, and from Unix domain # sockets. # # By default protected mode is enabled. You should disable it only if # you are sure you want clients from other hosts to connect to Redis # even if no authentication is configured, nor a specific set of interfaces # are explicitly listed using the "bind" directive. protected-mode yes # Accept connections on the specified port, default is 6379 (IANA #815344). # If port 0 is specified Redis will not listen on a TCP socket. 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-backlog 511 # Unix socket. # # 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) 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 300 seconds, which is the new # Redis default starting with Redis 3.2.1. tcp-keepalive 300 ################################# 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. daemonize no # If you run Redis from upstart or systemd, Redis can interact with your # supervision tree. Options: # supervised no - no supervision interaction # supervised upstart - signal upstart by putting Redis into SIGSTOP mode # supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET # supervised auto - detect upstart or systemd method based on # UPSTART_JOB or NOTIFY_SOCKET environment variables # Note: these supervision methods only signal "process is ready." # They do not enable continuous liveness pings back to your supervisor. supervised no # If a pid file is specified, Redis writes it where specified at startup # and removes it at exit. # # When the server runs non daemonized, no pid file is created if none is # specified in the configuration. When the server is daemonized, the pid file # is used even if not specified, defaulting to "/var/run/redis.pid". # # Creating a pid file is best effort: if Redis is not able to create it # nothing bad happens, the server will start and run normally. pidfile /var/run/redis_6379.pid # 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) 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 logfile "" # To enable logging to the system logger, just set 'syslog-enabled' to yes, # and optionally update the other syslog parameters to suit your needs. # syslog-enabled no # Specify the syslog 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 databases 16 # By default Redis shows an ASCII art logo only when started to log to the # standard output and if the standard output is a TTY. Basically this means # that normally a logo is displayed only in interactive sessions. # # However it is possible to force the pre-4.0 behavior and always show a # ASCII art logo in startup logs by setting the following option to yes. always-show-logo yes ################################ 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 "" 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. 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. 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. rdbchecksum yes # The filename where to dump the DB 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. dir ./ ################################# REPLICATION ################################# # Master-Replica replication. Use replicaof to make a Redis instance a copy of # another Redis server. A few things to understand ASAP about Redis replication. # # +------------------+ +---------------+ # | Master | ---> | Replica | # | (receive writes) | | (exact copy) | # +------------------+ +---------------+ # # 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 replicas. # 2) Redis replicas 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 replicas automatically try to reconnect to masters # and resynchronize with them. # # replicaof <masterip> <masterport> # If the master is password protected (using the "requirepass" configuration # directive below) it is possible to tell the replica to authenticate before # starting the replication synchronization process, otherwise the master will # refuse the replica request. # # masterauth <master-password> # When a replica loses its connection with the master, or when the replication # is still in progress, the replica can act in two different ways: # # 1) if replica-serve-stale-data is set to 'yes' (the default) the replica 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 replica-serve-stale-data is set to 'no' the replica will reply with # an error "SYNC with master in progress" to all the kind of commands # but to INFO, replicaOF, AUTH, PING, SHUTDOWN, REPLCONF, ROLE, CONFIG, # SUBSCRIBE, UNSUBSCRIBE, PSUBSCRIBE, PUNSUBSCRIBE, PUBLISH, PUBSUB, # COMMAND, POST, HOST: and LATENCY. # replica-serve-stale-data yes # You can configure a replica instance to accept writes or not. Writing against # a replica instance may be useful to store some ephemeral data (because data # written on a replica 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 replicas are read-only. # # Note: read only replicas 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 replica 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 replicas using 'rename-command' to shadow all the # administrative / dangerous commands. replica-read-only yes # Replication SYNC strategy: disk or socket. # # ------------------------------------------------------- # WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY # ------------------------------------------------------- # # New replicas and reconnecting replicas that are not able to continue the replication # process just receiving differences, need to do what is called a "full # synchronization". An RDB file is transmitted from the master to the replicas. # The transmission can happen in two different ways: # # 1) Disk-backed: The Redis master creates a new process that writes the RDB # file on disk. Later the file is transferred by the parent # process to the replicas incrementally. # 2) Diskless: The Redis master creates a new process that directly writes the # RDB file to replica sockets, without touching the disk at all. # # With disk-backed replication, while the RDB file is generated, more replicas # can be queued and served with the RDB file as soon as the current child producing # the RDB file finishes its work. With diskless replication instead once # the transfer starts, new replicas arriving will be queued and a new transfer # will start when the current one terminates. # # When diskless replication is used, the master waits a configurable amount of # time (in seconds) before starting the transfer in the hope that multiple replicas # will arrive and the transfer can be parallelized. # # With slow disks and fast (large bandwidth) networks, diskless replication # works better. repl-diskless-sync no # When diskless replication is enabled, it is possible to configure the delay # the server waits in order to spawn the child that transfers the RDB via socket # to the replicas. # # This is important since once the transfer starts, it is not possible to serve # new replicas arriving, that will be queued for the next RDB transfer, so the server # waits a delay in order to let more replicas arrive. # # The delay is specified in seconds, and by default is 5 seconds. To disable # it entirely just set it to 0 seconds and the transfer will start ASAP. repl-diskless-sync-delay 5 # Replicas send PINGs to server in a predefined interval. It's possible to change # this interval with the repl_ping_replica_period option. The default value is 10 # seconds. # # repl-ping-replica-period 10 # The following option sets the replication timeout for: # # 1) Bulk transfer I/O during SYNC, from the point of view of replica. # 2) Master timeout from the point of view of replicas (data, pings). # 3) Replica 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-replica-period otherwise a timeout will be detected # every time there is low traffic between the master and the replica. # # repl-timeout 60 # Disable TCP_NODELAY on the replica socket after SYNC? # # If you select "yes" Redis will use a smaller number of TCP packets and # less bandwidth to send data to replicas. But this can add a delay for # the data to appear on the replica side, up to 40 milliseconds with # Linux kernels using a default configuration. # # If you select "no" the delay for data to appear on the replica 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 replicas are many hops away, turning this to "yes" may # be a good idea. repl-disable-tcp-nodelay no # Set the replication backlog size. The backlog is a buffer that accumulates # replica data when replicas are disconnected for some time, so that when a replica # wants to reconnect again, often a full resync is not needed, but a partial # resync is enough, just passing the portion of data the replica missed while # disconnected. # # The bigger the replication backlog, the longer the time the replica can be # disconnected and later be able to perform a partial resynchronization. # # The backlog is only allocated once there is at least a replica connected. # # repl-backlog-size 1mb # After a master has no longer connected replicas 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 replica disconnected, for # the backlog buffer to be freed. # # Note that replicas never free the backlog for timeout, since they may be # promoted to masters later, and should be able to correctly "partially # resynchronize" with the replicas: hence they should always accumulate backlog. # # A value of 0 means to never release the backlog. # # repl-backlog-ttl 3600 # The replica priority is an integer number published by Redis in the INFO output. # It is used by Redis Sentinel in order to select a replica to promote into a # master if the master is no longer working correctly. # # A replica with a low priority number is considered better for promotion, so # for instance if there are three replicas 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 replica as not able to perform the # role of master, so a replica with priority of 0 will never be selected by # Redis Sentinel for promotion. # # By default the priority is 100. replica-priority 100 # It is possible for a master to stop accepting writes if there are less than # N replicas connected, having a lag less or equal than M seconds. # # The N replicas 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 replica, 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 replicas # are available, to the specified number of seconds. # # For example to require at least 3 replicas with a lag <= 10 seconds use: # # min-replicas-to-write 3 # min-replicas-max-lag 10 # # Setting one or the other to 0 disables the feature. # # By default min-replicas-to-write is set to 0 (feature disabled) and # min-replicas-max-lag is set to 10. # A Redis master is able to list the address and port of the attached # replicas in different ways. For example the "INFO replication" section # offers this information, which is used, among other tools, by # Redis Sentinel in order to discover replica instances. # Another place where this info is available is in the output of the # "ROLE" command of a master. # # The listed IP and address normally reported by a replica is obtained # in the following way: # # IP: The address is auto detected by checking the peer address # of the socket used by the replica to connect with the master. # # Port: The port is communicated by the replica during the replication # handshake, and is normally the port that the replica is using to # listen for connections. # # However when port forwarding or Network Address Translation (NAT) is # used, the replica may be actually reachable via different IP and port # pairs. The following two options can be used by a replica in order to # report to its master a specific set of IP and port, so that both INFO # and ROLE will report those values. # # There is no need to use both the options if you need to override just # the port or the IP address. # # replica-announce-ip 5.5.5.5 # replica-announce-port 1234 ################################## 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. # # 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 replicas may cause problems. ################################### CLIENTS #################################### # 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'. # # maxclients 10000 ############################## MEMORY MANAGEMENT ################################ # Set a memory usage limit to 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 or LFU cache, or to # set a hard memory limit for an instance (using the 'noeviction' policy). # # WARNING: If you have replicas attached to an instance with maxmemory on, # the size of the output buffers needed to feed the replicas 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 replicas 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 replicas attached it is suggested that you set a lower # limit for maxmemory so that there is some free RAM on the system for replica # output buffers (but this is not needed if the policy is 'noeviction'). # # maxmemory <bytes> # MAXMEMORY POLICY: how Redis will select what to remove when maxmemory # is reached. You can select among five behaviors: # # volatile-lru -> Evict using approximated LRU among the keys with an expire set. # allkeys-lru -> Evict any key using approximated LRU. # volatile-lfu -> Evict using approximated LFU among the keys with an expire set. # allkeys-lfu -> Evict any key using approximated LFU. # volatile-random -> Remove a random key among the ones 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 evict anything, just return an error on write operations. # # LRU means Least Recently Used # LFU means Least Frequently Used # # Both LRU, LFU and volatile-ttl are implemented using approximated # randomized algorithms. # # 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, LFU 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 more CPU. 3 is faster but not very accurate. # # maxmemory-samples 5 # Starting from Redis 5, by default a replica will ignore its maxmemory setting # (unless it is promoted to master after a failover or manually). It means # that the eviction of keys will be just handled by the master, sending the # DEL commands to the replica as keys evict in the master side. # # This behavior ensures that masters and replicas stay consistent, and is usually # what you want, however if your replica is writable, or you want the replica to have # a different memory setting, and you are sure all the writes performed to the # replica are idempotent, then you may change this default (but be sure to understand # what you are doing). # # Note that since the replica by default does not evict, it may end using more # memory than the one set via maxmemory (there are certain buffers that may # be larger on the replica, or data structures may sometimes take more memory and so # forth). So make sure you monitor your replicas and make sure they have enough # memory to never hit a real out-of-memory condition before the master hits # the configured maxmemory setting. # # replica-ignore-maxmemory yes ############################# LAZY FREEING #################################### # Redis has two primitives to delete keys. One is called DEL and is a blocking # deletion of the object. It means that the server stops processing new commands # in order to reclaim all the memory associated with an object in a synchronous # way. If the key deleted is associated with a small object, the time needed # in order to execute the DEL command is very small and comparable to most other # O(1) or O(log_N) commands in Redis. However if the key is associated with an # aggregated value containing millions of elements, the server can block for # a long time (even seconds) in order to complete the operation. # # For the above reasons Redis also offers non blocking deletion primitives # such as UNLINK (non blocking DEL) and the ASYNC option of FLUSHALL and # FLUSHDB commands, in order to reclaim memory in background. Those commands # are executed in constant time. Another thread will incrementally free the # object in the background as fast as possible. # # DEL, UNLINK and ASYNC option of FLUSHALL and FLUSHDB are user-controlled. # It's up to the design of the application to understand when it is a good # idea to use one or the other. However the Redis server sometimes has to # delete keys or flush the whole database as a side effect of other operations. # Specifically Redis deletes objects independently of a user call in the # following scenarios: # # 1) On eviction, because of the maxmemory and maxmemory policy configurations, # in order to make room for new data, without going over the specified # memory limit. # 2) Because of expire: when a key with an associated time to live (see the # EXPIRE command) must be deleted from memory. # 3) Because of a side effect of a command that stores data on a key that may # already exist. For example the RENAME command may delete the old key # content when it is replaced with another one. Similarly SUNIONSTORE # or SORT with STORE option may delete existing keys. The SET command # itself removes any old content of the specified key in order to replace # it with the specified string. # 4) During replication, when a replica performs a full resynchronization with # its master, the content of the whole database is removed in order to # load the RDB file just transferred. # # In all the above cases the default is to delete objects in a blocking way, # like if DEL was called. However you can configure each case specifically # in order to instead release memory in a non-blocking way like if UNLINK # was called, using the following configuration directives: lazyfree-lazy-eviction no lazyfree-lazy-expire no lazyfree-lazy-server-del no replica-lazy-flush no ############################## 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 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". # 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 # An AOF file may be found to be truncated at the end during the Redis # startup process, when the AOF data gets loaded back into memory. # This may happen when the system where Redis is running # crashes, especially when an ext4 filesystem is mounted without the # data=ordered option (however this can't happen when Redis itself # crashes or aborts but the operating system still works correctly). # # Redis can either exit with an error when this happens, or load as much # data as possible (the default now) and start if the AOF file is found # to be truncated at the end. The following option controls this behavior. # # If aof-load-truncated is set to yes, a truncated AOF file is loaded and # the Redis server starts emitting a log to inform the user of the event. # Otherwise if the option is set to no, the server aborts with an error # and refuses to start. When the option is set to no, the user requires # to fix the AOF file using the "redis-check-aof" utility before to restart # the server. # # Note that if the AOF file will be found to be corrupted in the middle # the server will still exit with an error. This option only applies when # Redis will try to read more data from the AOF file but not enough bytes # will be found. aof-load-truncated yes # When rewriting the AOF file, Redis is able to use an RDB preamble in the # AOF file for faster rewrites and recoveries. When this option is turned # on the rewritten AOF file is composed of two different stanzas: # # [RDB file][AOF tail] # # When loading Redis recognizes that the AOF file starts with the "REDIS" # string and loads the prefixed RDB file, and continues loading the AOF # tail. aof-use-rdb-preamble yes ################################ 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. lua-time-limit 5000 ################################ REDIS CLUSTER ############################### # # ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ # WARNING EXPERIMENTAL: Redis Cluster is considered to be stable code, however # in order to mark it as "mature" we need to wait for a non trivial percentage # of users to deploy it in production. # ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ # # Normal Redis instances can't be part of a Redis Cluster; only nodes that are # started as cluster nodes can. In order to start a Redis instance as a # cluster node enable the cluster support uncommenting the following: # # 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 do 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 replica of a failing master will avoid to start a failover if its data # looks too old. # # There is no simple way for a replica to actually have an exact measure of # its "data age", so the following two checks are performed: # # 1) If there are multiple replicas able to failover, they exchange messages # in order to try to give an advantage to the replica with the best # replication offset (more data from the master processed). # Replicas 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 replica 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 replica will not try to failover # at all. # # The point "2" can be tuned by user. Specifically a replica will not perform # the failover if, since the last interaction with the master, the time # elapsed is greater than: # # (node-timeout * replica-validity-factor) + repl-ping-replica-period # # So for example if node-timeout is 30 seconds, and the replica-validity-factor # is 10, and assuming a default repl-ping-replica-period of 10 seconds, the # replica will not try to failover if it was not able to talk with the master # for longer than 310 seconds. # # A large replica-validity-factor may allow replicas with too old data to failover # a master, while a too small value may prevent the cluster from being able to # elect a replica at all. # # For maximum availability, it is possible to set the replica-validity-factor # to a value of 0, which means, that replicas 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-replica-validity-factor 10 # Cluster replicas are able to migrate to orphaned masters, that are masters # that are left without working replicas. 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 replicas. # # Replicas migrate to orphaned masters only if there are still at least a # given number of other working replicas for their old master. This number # is the "migration barrier". A migration barrier of 1 means that a replica # will migrate only if there is at least 1 other working replica for its master # and so forth. It usually reflects the number of replicas you want for every # master in your cluster. # # Default is 1 (replicas migrate only if their masters remain with at least # one replica). 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 # By default Redis Cluster nodes stop accepting queries if they detect there # is at least an hash slot uncovered (no available node is serving it). # This way if the cluster is partially down (for example a range of hash slots # are no longer covered) all the cluster becomes, eventually, unavailable. # It automatically returns available as soon as all the slots are covered again. # # However sometimes you want the subset of the cluster which is working, # to continue to accept queries for the part of the key space that is still # covered. In order to do so, just set the cluster-require-full-coverage # option to no. # # cluster-require-full-coverage yes # This option, when set to yes, prevents replicas from trying to failover its # master during master failures. However the master can still perform a # manual failover, if forced to do so. # # This is useful in different scenarios, especially in the case of multiple # data center operations, where we want one side to never be promoted if not # in the case of a total DC failure. # # cluster-replica-no-failover no # In order to setup your cluster make sure to read the documentation # available at http://redis.io web site. ########################## CLUSTER DOCKER/NAT support ######################## # In certain deployments, Redis Cluster nodes address discovery fails, because # addresses are NAT-ted or because ports are forwarded (the typical case is # Docker and other containers). # # In order to make Redis Cluster working in such environments, a static # configuration where each node knows its public address is needed. The # following two options are used for this scope, and are: # # * cluster-announce-ip # * cluster-announce-port # * cluster-announce-bus-port # # Each instruct the node about its address, client port, and cluster message # bus port. The information is then published in the header of the bus packets # so that other nodes will be able to correctly map the address of the node # publishing the information. # # If the above options are not used, the normal Redis Cluster auto-detection # will be used instead. # # Note that when remapped, the bus port may not be at the fixed offset of # clients port + 10000, so you can specify any port and bus-port depending # on how they get remapped. If the bus-port is not set, a fixed offset of # 10000 will be used as usually. # # Example: # # cluster-announce-ip 10.1.1.5 # cluster-announce-port 6379 # cluster-announce-bus-port 6380 ################################## 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 ################################ LATENCY MONITOR ############################## # The Redis latency monitoring subsystem samples different operations # at runtime in order to collect data related to possible sources of # latency of a Redis instance. # # Via the LATENCY command this information is available to the user that can # print graphs and obtain reports. # # The system only logs operations that were performed in a time equal or # greater than the amount of milliseconds specified via the # latency-monitor-threshold configuration directive. When its value is set # to zero, the latency monitor is turned off. # # By default latency monitoring is disabled since it is mostly not needed # if you don't have latency issues, and collecting data has a performance # impact, that while very small, can be measured under big load. Latency # monitoring can easily be enabled at runtime using the command # "CONFIG SET latency-monitor-threshold <milliseconds>" if needed. latency-monitor-threshold 0 ############################# EVENT NOTIFICATION ############################## # Redis can notify Pub/Sub clients about events happening in the key space. # This feature is documented at http://redis.io/topics/notifications # # For instance if keyspace events notification is enabled, and a client # performs a DEL operation on key "foo" stored in the Database 0, two # messages will be published via Pub/Sub: # # PUBLISH __keyspace@0__:foo del # PUBLISH __keyevent@0__:del foo # # It is possible to select the events that Redis will notify among a set # of classes. Every class is identified by a single character: # # K Keyspace events, published with __keyspace@<db>__ prefix. # E Keyevent events, published with __keyevent@<db>__ prefix. # g Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ... # $ String commands # l List commands # s Set commands # h Hash commands # z Sorted set commands # x Expired events (events generated every time a key expires) # e Evicted events (events generated when a key is evicted for maxmemory) # A Alias for g$lshzxe, so that the "AKE" string means all the events. # # The "notify-keyspace-events" takes as argument a string that is composed # of zero or multiple characters. The empty string means that notifications # are disabled. # # Example: to enable list and generic events, from the point of view of the # event name, use: # # notify-keyspace-events Elg # # Example 2: to get the stream of the expired keys subscribing to channel # name __keyevent@0__:expired use: # # notify-keyspace-events Ex # # By default all notifications are disabled because most users don't need # this feature and the feature has some overhead. Note that if you don't # specify at least one of K or E, no events will be delivered. 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 # Lists are also encoded in a special way to save a lot of space. # The number of entries allowed per internal list node can be specified # as a fixed maximum size or a maximum number of elements. # For a fixed maximum size, use -5 through -1, meaning: # -5: max size: 64 Kb <-- not recommended for normal workloads # -4: max size: 32 Kb <-- not recommended # -3: max size: 16 Kb <-- probably not recommended # -2: max size: 8 Kb <-- good # -1: max size: 4 Kb <-- good # Positive numbers mean store up to _exactly_ that number of elements # per list node. # The highest performing option is usually -2 (8 Kb size) or -1 (4 Kb size), # but if your use case is unique, adjust the settings as necessary. list-max-ziplist-size -2 # Lists may also be compressed. # Compress depth is the number of quicklist ziplist nodes from *each* side of # the list to *exclude* from compression. The head and tail of the list # are always uncompressed for fast push/pop operations. Settings are: # 0: disable all list compression # 1: depth 1 means "don't start compressing until after 1 node into the list, # going from either the head or tail" # So: [head]->node->node->...->node->[tail] # [head], [tail] will always be uncompressed; inner nodes will compress. # 2: [head]->[next]->node->node->...->node->[prev]->[tail] # 2 here means: don't compress head or head->next or tail->prev or tail, # but compress all nodes between them. # 3: [head]->[next]->[next]->node->node->...->node->[prev]->[prev]->[tail] # etc. list-compress-depth 0 # 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-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 # Streams macro node max size / items. The stream data structure is a radix # tree of big nodes that encode multiple items inside. Using this configuration # it is possible to configure how big a single node can be in bytes, and the # maximum number of items it may contain before switching to a new node when # appending new stream entries. If any of the following settings are set to # zero, the limit is ignored, so for instance it is possible to set just a # max entires limit by setting max-bytes to 0 and max-entries to the desired # value. stream-node-max-bytes 4096 stream-node-max-entries 100 # 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. activerehashing yes # The client output buffer limits can be used to force disconnection of clients # that are not reading data from the server fast enough for some reason (a # common reason is that a Pub/Sub client can't consume messages as fast as the # publisher can produce them). # # The limit can be set differently for the three different classes of clients: # # normal -> normal clients including MONITOR clients # replica -> replica 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 replica clients, since # subscribers and replicas 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 replica 256mb 64mb 60 client-output-buffer-limit pubsub 32mb 8mb 60 # Client query buffers accumulate new commands. They are limited to a fixed # amount by default in order to avoid that a protocol desynchronization (for # instance due to a bug in the client) will lead to unbound memory usage in # the query buffer. However you can configure it here if you have very special # needs, such us huge multi/exec requests or alike. # # client-query-buffer-limit 1gb # In the Redis protocol, bulk requests, that are, elements representing single # strings, are normally limited ot 512 mb. However you can change this limit # here. # # proto-max-bulk-len 512mb # 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 according 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 # Normally it is useful to have an HZ value which is proportional to the # number of clients connected. This is useful in order, for instance, to # avoid too many clients are processed for each background task invocation # in order to avoid latency spikes. # # Since the default HZ value by default is conservatively set to 10, Redis # offers, and enables by default, the ability to use an adaptive HZ value # which will temporary raise when there are many connected clients. # # When dynamic HZ is enabled, the actual configured HZ will be used as # as a baseline, but multiples of the configured HZ value will be actually # used as needed once more clients are connected. In this way an idle # instance will use very little CPU time while a busy instance will be # more responsive. dynamic-hz 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-incremental-fsync yes # When redis saves RDB 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. rdb-save-incremental-fsync yes # Redis LFU eviction (see maxmemory setting) can be tuned. However it is a good # idea to start with the default settings and only change them after investigating # how to improve the performances and how the keys LFU change over time, which # is possible to inspect via the OBJECT FREQ command. # # There are two tunable parameters in the Redis LFU implementation: the # counter logarithm factor and the counter decay time. It is important to # understand what the two parameters mean before changing them. # # The LFU counter is just 8 bits per key, it's maximum value is 255, so Redis # uses a probabilistic increment with logarithmic behavior. Given the value # of the old counter, when a key is accessed, the counter is incremented in # this way: # # 1. A random number R between 0 and 1 is extracted. # 2. A probability P is calculated as 1/(old_value*lfu_log_factor+1). # 3. The counter is incremented only if R < P. # # The default lfu-log-factor is 10. This is a table of how the frequency # counter changes with a different number of accesses with different # logarithmic factors: # # +--------+------------+------------+------------+------------+------------+ # | factor | 100 hits | 1000 hits | 100K hits | 1M hits | 10M hits | # +--------+------------+------------+------------+------------+------------+ # | 0 | 104 | 255 | 255 | 255 | 255 | # +--------+------------+------------+------------+------------+------------+ # | 1 | 18 | 49 | 255 | 255 | 255 | # +--------+------------+------------+------------+------------+------------+ # | 10 | 10 | 18 | 142 | 255 | 255 | # +--------+------------+------------+------------+------------+------------+ # | 100 | 8 | 11 | 49 | 143 | 255 | # +--------+------------+------------+------------+------------+------------+ # # NOTE: The above table was obtained by running the following commands: # # redis-benchmark -n 1000000 incr foo # redis-cli object freq foo # # NOTE 2: The counter initial value is 5 in order to give new objects a chance # to accumulate hits. # # The counter decay time is the time, in minutes, that must elapse in order # for the key counter to be divided by two (or decremented if it has a value # less <= 10). # # The default value for the lfu-decay-time is 1. A Special value of 0 means to # decay the counter every time it happens to be scanned. # # lfu-log-factor 10 # lfu-decay-time 1 ########################### ACTIVE DEFRAGMENTATION ####################### # # WARNING THIS FEATURE IS EXPERIMENTAL. However it was stress tested # even in production and manually tested by multiple engineers for some # time. # # What is active defragmentation? # ------------------------------- # # Active (online) defragmentation allows a Redis server to compact the # spaces left between small allocations and deallocations of data in memory, # thus allowing to reclaim back memory. # # Fragmentation is a natural process that happens with every allocator (but # less so with Jemalloc, fortunately) and certain workloads. Normally a server # restart is needed in order to lower the fragmentation, or at least to flush # away all the data and create it again. However thanks to this feature # implemented by Oran Agra for Redis 4.0 this process can happen at runtime # in an "hot" way, while the server is running. # # Basically when the fragmentation is over a certain level (see the # configuration options below) Redis will start to create new copies of the # values in contiguous memory regions by exploiting certain specific Jemalloc # features (in order to understand if an allocation is causing fragmentation # and to allocate it in a better place), and at the same time, will release the # old copies of the data. This process, repeated incrementally for all the keys # will cause the fragmentation to drop back to normal values. # # Important things to understand: # # 1. This feature is disabled by default, and only works if you compiled Redis # to use the copy of Jemalloc we ship with the source code of Redis. # This is the default with Linux builds. # # 2. You never need to enable this feature if you don't have fragmentation # issues. # # 3. Once you experience fragmentation, you can enable this feature when # needed with the command "CONFIG SET activedefrag yes". # # The configuration parameters are able to fine tune the behavior of the # defragmentation process. If you are not sure about what they mean it is # a good idea to leave the defaults untouched. # Enabled active defragmentation # activedefrag yes # Minimum amount of fragmentation waste to start active defrag # active-defrag-ignore-bytes 100mb # Minimum percentage of fragmentation to start active defrag # active-defrag-threshold-lower 10 # Maximum percentage of fragmentation at which we use maximum effort # active-defrag-threshold-upper 100 # Minimal effort for defrag in CPU percentage # active-defrag-cycle-min 5 # Maximal effort for defrag in CPU percentage # active-defrag-cycle-max 75 # Maximum number of set/hash/zset/list fields that will be processed from # the main dictionary scan # active-defrag-max-scan-fields 1000
(1). 允許遠程訪問
#1. 注釋掉下面代碼，或者改為 bind 0.0.0.0
#bind 127.0.0.1
#2. 關閉保護模式
protected-mode no
#3. 開啟密碼(開啟密碼后，上面的保護模式可以不用關閉，遠程也可以連接)
requirepass 123456
PS：還需保證端口開放或者防火牆關閉。
(2). redis cluster配置
# 一. 允許遠程訪問
#1. 注釋掉下面代碼，或者改為 bind 0.0.0.0
#bind 127.0.0.1
#2. 關閉保護模式
protected-mode no
#二. 通用配置
#1. 開啟守護進程
daemonize yes
#2. 配置密碼（必須設置相同的密碼，不設masterauth的話宕機了不能自動恢復）
requirepass 123456
masterauth 123456
#三.集群配置
port 6384 #配置端口
cluster-enabled yes #開啟集群
cluster-config-file nodes-6384.conf #集群節點配置文件
pidfile /var/run/redis_6384.pid
cluster-node-timeout 5000 #集群節點超時時間
(3). 數據持久化
#一. RDB存儲 # 下面配置為默認配置，默認就是開啟的，在一定的間隔時間中，檢測key的變化情況，然后持久化數據 save 900 1 #900s后至少1個key發生變化則進行存儲 save 300 10 #300s后至少10個key發生變化則進行存儲 save 60 10000 #60s后至少10000個key發生變化則進行存儲 #二. AOP存儲 #默認是關閉的，日志記錄的方式，可以記錄每一條命令的操作。可以每一次命令操作后，持久化數據，啟用的話通常使用每隔一秒持久化一次的策略 appendonly no（默認no） --> appendonly yes （開啟aof） # appendfsync always #每一次操作都進行持久化 appendfsync everysec #每隔一秒進行一次持久化 # appendfsync no # 不進行持久化
(4). 緩存淘汰策略
# - volatile-lru: 針對到期的鍵值，采取 LRU 策略； # - volatile-lfu: 針對到期的鍵值，采取 LFU 策略； # - volatile-random: 針對到期的鍵值，采取隨機策略； # - allkeys-lru: 針對所有鍵值，采取 LRU 策略； # - allkeys-lfu: 針對所有鍵值，采取 LFU 策略； # - allkeys-random: 針對所有鍵值，采取隨機策略； # - volatile-ttl: 刪除最近到期的key（次要TTL） # - noeviction: 不清除任何內容，只是在寫入操作時報錯。 # # LRU表示最近最少使用 # LFU意味着最少使用 # # LRU，LFU和volatile-ttl都是使用近似隨機算法實現的。 # # 默認值是：noeviction # # maxmemory-policy noeviction
(5). 常用配置匯總
#修改daemonize為yes，即默認以后台程序方式運行 daemonize yes #修改默認監聽端口(一般用默認的) port 6379 #修改生成默認日志文件位置，默認為"" logfile "" #默認rdb存儲方式的名稱 dbfilename dump.rdb #rdb文件存放位置,默認為當前目錄 dir ./ #開啟aof存儲，默認為no appendonly no #aof存儲持久化文件的名稱 appendfilename "appendonly.aof" #PID文件 pidfile /home/apps/redis/redis.pid #保護模式 protected-mode no #支持集群 cluster-enabled yes #密碼 requirepass 123456 #集群相關密碼 masterauth 123456 #緩存淘汰策略（默認不清除） maxmemory-policy noeviction
(6). 全部文件翻譯（來源於網絡）
# 請注意，為了讀取配置文件，必須以文件路徑作為第一個參數啟動Redis： # ./redis-server /path/to/redis.conf # 內存大小單位 # # 1k => 1000 bytes # 1kb => 1024 bytes # 1m => 1000000 bytes # 1mb => 1024*1024 bytes # 1g => 1000000000 bytes # 1gb => 1024*1024*1024 bytes # # 單位不區分大小寫，因此 1GB 1Gb 1gB 是一樣的. ################################## INCLUDES ################################### # 在此處包含一個或多個其他配置文件。如果您有一個標准模板可用於所有Redis服務器，但還需要自定義一些服務器設置。 # # “include”不會被來自admin或Redis Sentinel的命令“CONFIG REWRITE”重寫。 # 由於Redis始終使用最后處理的行為作為配置指令的值，因此最好將include放在此文件的開頭，以避免在運行時覆蓋配置更改。 # # 如果你要使用includes來覆蓋配置選項，最好將include作為最后一行。 # # include /path/to/local.conf # include /path/to/other.conf ################################## MODULES ##################################### # 啟動時加載指定模塊，如果服務器無法加載模塊，它將中止。 這里可以使用多個loadmodule指令。 # # loadmodule /path/to/my_module.so # loadmodule /path/to/other_module.so ################################## NETWORK ##################################### # 默認情況下，如果未指定“bind”配置指令，則Redis將監聽來自服務器上可用的所有端口的連接。 # 可以使用“bind”配置指令僅監聽一個或多個指定的IP地址。 # # Examples: # # bind 192.168.1.100 10.0.0.1 # bind 127.0.0.1 ::1 # # ~~~ WARNING ~~~ 如果運行Redis的計算機直接暴露於Internet，則綁定到所有接口是危險的，並且會將實例暴露給Internet上的每個人。 # 因此，默認情況下，我們不會注釋以下綁定指令，這意味着Redis只能接受來自指定ip的客戶端的連接 # # IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES # JUST COMMENT THE FOLLOWING LINE. # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ bind 127.0.0.1 # 保護模式是一層安全保護，以避免在Internet上打開的Redis實例被訪問和利用。 # # 當保護模式打開的情況下,如果： # # 1) 服務器未使用“bind”指令顯式綁定到一組地址。 # 2) 沒有配置密碼。 # # 服務器僅接受來自IPv4和IPv6環回地址127.0.0.1和:: 1以及Unix域套接字的客戶端的連接。 # # 默認情況下保護模式是開啟的。 只有在希望其他主機的客戶端即使未配置任何身份驗證，仍要連接到Redis時，應該禁用此選項並且不使用“bind”指令明確列出一組特定的接口。 protected-mode yes # 接受指定端口上的連接，默認為6379 # 如果指定了端口0，則Redis不會偵聽TCP套接字。 port 6379 # TCP連接最大積壓數 # # 在大量客戶端連接的情況下，應該提高該值，以免客戶端連接慢。 # 但該值受系統內核參數的限制，包括 somaxconn 和 tcp_max_syn_backlog。 tcp-backlog 511 # Unix socket. # # 指定將用於監聽傳入連接的Unix套接字的路徑。 沒有默認值，因此Redis在未指定時不會偵聽unix套接字。 # # unixsocket /tmp/redis.sock # unixsocketperm 700 # 當連接的客戶端連續空閑指定時間后，就斷開該連接。指定值為0時禁用超時機制。 timeout 0 # TCP keepalive. # 周期性檢測客戶端是否可用 # 如果非零，則在沒有通信的情況下使用SO_KEEPALIVE向客戶端發送TCP ACK。 # 此選項的合理值為300秒 tcp-keepalive 300 ################################# GENERAL ##################################### # 設定是否以守護進程啟動服務（默認是no），守護進程會生成 PID 文件 /var/run/redis_6379.pid。 daemonize no # If you run Redis from upstart or systemd, Redis can interact with your # supervision tree. Options: # supervised no - no supervision interaction # supervised upstart - signal upstart by putting Redis into SIGSTOP mode # supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET # supervised auto - detect upstart or systemd method based on # UPSTART_JOB or NOTIFY_SOCKET environment variables # Note: these supervision methods only signal "process is ready." # They do not enable continuous liveness pings back to your supervisor. supervised no # 啟用守護進程模式時，會生成該文件。 pidfile /var/run/redis_6379.pid # 指定日志級別 # 日志級別有以下選項: # debug (適用於開發/測試) # verbose (很少但很有用的信息) # notice (信息適中，推薦選項) # warning (只記錄非常重要/關鍵的消息) loglevel notice # 指定保存日志的文件。請注意，如果您使用標准輸出進行日志記錄，守護進程情況下，日志將發送到/dev/null logfile "" # 要啟用日志記錄到系統記錄器，只需將“syslog-enabled”設置為yes，並可選擇更新其他syslog參數以滿足您的需要。 # syslog-enabled no # 指定syslog標識。 # syslog-ident redis # 指定syslog工具。 必須是USER或LOCAL0-LOCAL7之間。 # syslog-facility local0 # 設置數據庫數量，默認為16. 默認數據庫是 DB 0, 你可以使用 SELECT <dbid> 選擇使用的數據庫。 # 數據庫編號在 0 到 'databases'-1 databases 16 # 啟動日志中是否顯示redis logo，默認是開啟的 always-show-logo yes ################################ SNAPSHOTTING ################################ # # 數據持久化: # # save <seconds> <changes> # # 指定時間間隔后，如果數據變化達到指定次數，則導出生成快照文件 # # 示例如下： # # 900 秒(15 分鍾)內至少有1個key被修改 # 300 秒(5分鍾)內至少有10個key被修改 # 60 秒(1分鍾)內至少有10000個key被修改 # # # 如果指定 save ""，則相當於清除前面指定的所有 save 設置 # # save "" save 900 1 save 300 10 save 60 10000 # 在啟用快照的情況下(指定了有效的 save)，如果遇到某次快照生成失敗(比如目錄無權限)， # 之后的數據修改就會被禁止。這有利於用戶及早發現快照保存失敗，以免更多的數據不能持久化而丟失的風險。 # 當快照恢復正常后，數據的修改會自動開啟。 # 如果你有其他的持久化監控，你可以關閉本機制。 stop-writes-on-bgsave-error yes # 快照中字符串值是否壓縮 rdbcompression yes # 如果開啟，校驗和會被放在文件尾部。這將使快照數據更可靠，但會在快照生成與加載時降低大約 10% 的性能，追求高性能時可關閉該功能。 rdbchecksum yes # 指定保存快照文件的名稱 dbfilename dump.rdb # 指定保存快照文件的目錄，AOF(Append Only File) 文件也會生成到該目錄 dir ./ ################################# REPLICATION ################################# # 主從復制。 使用 replicaof 使Redis實例成為另一台Redis服務器的副本。 # # +------------------+ +---------------+ # | Master | ---> | Replica | # | (receive writes) | | (exact copy) | # +------------------+ +---------------+ # # 1) Redis復制是異步的，但是如果master與一定數量的副本無法連接，則可以將主服務器配置為停止接受寫入。 # 2) 如果再較短時間內與副本失去了連接，當Redis副本與master重新連接時可以執行部分重新同步。因此就要求配置一個合理的 backlog 值。 # 3) 當副本節點重新連接到master時，重新同步復制時自動的，不需要用戶干預。 # # replicaof <masterip> <masterport> # 如果主服務器受密碼保護（使用下面的“requirepass”配置指令），則可以在啟動復制同步過程之前告知副本服務器進行身份驗證，否則主服務器將拒絕副本服務器請求。 # # masterauth <master-password> # 當從庫與主庫連接中斷，或者主從同步正在進行時，如果有客戶端向從庫讀取數據： # - yes: 從庫答復現有數據，可能是舊數據(初始從未修改的值則為空值) # - no: 從庫報錯“正在從主庫同步” replica-serve-stale-data yes # 從庫只允許讀取 replica-read-only yes # 無盤同步 # # ------------------------------------------------------- # WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY # ------------------------------------------------------- # 新連接(包括連接中斷后重連)的從庫不可采用增量同步，只能采用全量同步(RDB文件由主庫傳給從庫)，有兩種傳遞方式： # - 磁盤形式：主庫創建子進程，子進程寫入磁盤 RDB 文件，再由父進程立即傳給從庫； # - 無磁盤形式：主庫創建子進程，子進程把 RDB 文件直接寫入從庫的 SOCKET 連接。 repl-diskless-sync no # 無盤同步傳輸間隔（秒） repl-diskless-sync-delay 5 # 從庫向主庫PING的間隔（秒） # # repl-ping-replica-period 10 # 以下選項設置復制超時： # # 1) 從副本的角度來看，在SYNC期間批量傳輸I / O. # 2) 從副本（data，ping）的角度來看master超時。 # 3) 從主服務器的角度來看副本超時（REPLCONF ACK ping）。 # # 確保此值大於為repl-ping-replica-period指定的值非常重要，否則每次主服務器和副本服務器之間的流量較低時都會檢測到超時。 # # repl-timeout 60 # 在SYNC之后禁用副本套接字上的TCP_NODELAY？ # # 如果選擇“yes”，Redis將使用較少數量的TCP數據包和較少的帶寬將數據發送到副本。 但這可能會增加數據在副本端出現的延遲，使用默認配置的Linux內核最多可達40毫秒。 # # 如果選擇“no”，則副本上顯示的數據延遲將減少，但將使用更多帶寬進行復制。 # # 默認情況下，我們針對低延遲進行優化，但是在非常高的流量條件下，或者當主節點和副本很多時，將其設置為 yes 或許是較好的選擇 repl-disable-tcp-nodelay no # 設置復制積壓大小（backlog）。 積壓是一個緩沖區，當副本斷開連接一段時間后會累積副本數據，因此當副本想要再次重新連接時，通常不需要完全重新同步，只需要部分重新同步就足夠了 # # 復制backlog越大，副本可以斷開連接的時間越長。 # # repl-backlog-size 1mb # 當master與副本節點斷開時間超過指定時間后，將釋放復制積壓緩沖區（backlog） # # 如果設置為0，表示一直不釋放復制積壓緩沖區 # # repl-backlog-ttl 3600 # 副本優先級，哨兵模式下，如果主服務器不再正常工作，Redis Sentinel 將優先使用它來選擇要升級為主服務器的副本。 # # 值越低，優先級越高 # # 優先級為0會將副本標記為無法擔任master的角色，因此Redis Sentinel永遠不會選擇優先級為0的副本進行升級。 # # 默認情況下，優先級為100。 replica-priority 100 # 如果可用連接的副本數少於N個，並且延遲小於或等於M秒，則master停止接受寫入。 # # 以秒為單位的延遲（必須<=指定值）是根據從副本接收的最后一次ping計算的，通常每秒發送一次。 # # 例如，要求至少3個在線且滯后時間<= 10秒的副本： # # min-replicas-to-write 3 # min-replicas-max-lag 10 # # 以上兩個屬性，任意一個設置為0，都會禁用該功能。 # # 默認情況下，min-replicas-to-write設置為0（功能已禁用），min-replicas-max-lag設置為10。 # 當使用端口轉發或網絡地址轉換（NAT）時，實際上可以通過不同的IP和端口對副本進行訪問。 # 副本可以使用以下兩個選項，向其主服務器報告一組特定的IP和端口。 # # 如果只需要覆蓋端口或IP地址，則無需使用這兩個選項。 # # replica-announce-ip 5.5.5.5 # replica-announce-port 1234 ################################## SECURITY ################################### # 設置redis訪問密碼 # # requirepass foobared # 命令重命名. # 對於一些敏感的命令，不希望任意客戶端都可以執行，可以改掉默認的名字，新名字只告知特定的客戶端來執行。 # 可以命令改名：rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52 # 可以禁用命令：rename-command CONFIG ""，即新名稱為空串。 # 需要注意的是，命令改名保存至 AOF 文件或傳輸至從庫，可能導致問題。 # rename-command CONFIG "" ################################### CLIENTS #################################### # 同一時刻最多可以接納的客戶端數目(Redis 服務要占用其中的大約 32 個文件描述符)。 # 如果客戶端連接數達到該上限，新來客戶端將被告知“已達到最大客戶端連接數”。 # # maxclients 10000 ############################## MEMORY MANAGEMENT ################################ # 內存使用上限 # # 當內存達到上限時，Redis 將使用指定的策略清除其他鍵值。 # 如果 Redis 無法清除(或者策略不允許清除鍵值)，將對占用內存的命令報錯，但對只讀的命令正常服務。 # # maxmemory <bytes> # - volatile-lru: 針對到期的鍵值，采取 LRU 策略； # - volatile-lfu: 針對到期的鍵值，采取 LFU 策略； # - volatile-random: 針對到期的鍵值，采取隨機策略； # - allkeys-lru: 針對所有鍵值，采取 LRU 策略； # - allkeys-lfu: 針對所有鍵值，采取 LFU 策略； # - allkeys-random: 針對所有鍵值，采取隨機策略； # - volatile-ttl: 刪除最近到期的key（次要TTL） # - noeviction: 不清除任何內容，只是在寫入操作時報錯。 # # LRU表示最近最少使用 # LFU意味着最少使用 # # LRU，LFU和volatile-ttl都是使用近似隨機算法實現的。 # # 默認值是：noeviction # # maxmemory-policy noeviction # 清除鍵值時取樣數量 # LRU，LFU和最小TTL算法不是精確的算法，而是近似算法（為了節省內存），因此您可以調整它以獲得速度或精度。 # 默認情況下，Redis將檢查五個鍵並選擇最近使用的鍵，您可以使用以下配置指令更改樣本大小。 # 默認值為5會產生足夠好的結果。 10:近似非常接近真實的LRU但成本更高的CPU。 3:更快但不是很准確。 # # maxmemory-samples 5 # 從Redis 5開始，默認情況下，副本將忽略其maxmemory設置（除非在故障轉移后或手動將其提升為主設備）。 # 這意味着key的清除將由主服務器處理，當主服務器中的key清除時，將DEL命令發送到副本。 # # 此行為可確保主服務器和副本服務器保持一致，但是如果您的副本服務器是可寫的，或者您希望副本服務器具有不同的內存設置， # 並且您確定對副本服務器執行的所有寫操作都是冪等的， 然后你可以改變這個默認值（但一定要明白你在做什么）。 # # replica-ignore-maxmemory yes ############################# LAZY FREEING #################################### # lazy free 為惰性刪除或延遲釋放； # 當刪除鍵的時候,redis提供異步延時釋放key內存的功能， # 把key釋放操作放在bio(Background I/O)單獨的子線程處理中， # 減少刪除big key對redis主線程的阻塞。有效地避免刪除big key帶來的性能和可用性問題。 # lazy free的使用分為2類：第一類是與DEL命令對應的主動刪除，第二類是過期key刪除。 # 針對redis內存使用達到maxmeory，並設置有淘汰策略時；在被動淘汰鍵時，是否采用lazy free機制； lazyfree-lazy-eviction no # 針對設置有TTL的鍵，達到過期后，被redis清理刪除時是否采用lazy free機制； lazyfree-lazy-expire no # 針對有些指令在處理已存在的鍵時，會帶有一個隱式的DEL鍵的操作。如rename命令，當目標鍵已存在,redis會先刪除目標鍵，如果這些目標鍵是一個big key,那就會引入阻塞刪除的性能問題 lazyfree-lazy-server-del no # 針對slave進行全量數據同步，slave在加載master的RDB文件前，會運行flushall來清理自己的數據場景， replica-lazy-flush no ############################## APPEND ONLY MODE ############################### # 可以同時啟用AOF和RDB持久性而不會出現問題。 如果在啟動時檢查到啟用了AOF，Redis將優先加載AOF。 # AOF 持久化機制默認是關閉的 # appendonly no # AOF持久化文件名稱默認為 appendonly.aof appendfilename "appendonly.aof" # fsync() 調用會告訴操作系統將緩沖區的數據同步到磁盤，可取三種值：always、everysec和no。 # always：實時會極大消弱Redis的性能，因為這種模式下每次write后都會調用fsync。 # no：write后不會有fsync調用，由操作系統自動調度刷磁盤，性能是最好的。 # everysec：每秒調用一次fsync（默認） # appendfsync always appendfsync everysec # appendfsync no # 在AOF文件 rewrite期間,是否對aof新記錄的append暫緩使用文件同步策略,主要考慮磁盤IO開支和請求阻塞時間。默認為no,表示"不暫緩",新的aof記錄仍然會被立即同步 no-appendfsync-on-rewrite no # 當AOF增長超過指定比例時，重寫AOF文件，設置為0表示不自動重寫AOF文件，重寫是為了使aof體積保持最小，而確保保存最完整的數據。 # 這里表示增長一倍 auto-aof-rewrite-percentage 100 #觸發aof rewrite的最小文件大小，這里表示，文件大小最小64mb才會觸發重寫機制 auto-aof-rewrite-min-size 64mb # AOF文件可能在尾部是不完整的。那redis重啟時load進內存的時候就有問題了。 # # 如果選擇的是yes，當截斷的aof文件被導入的時候，會自動發布一個log給客戶端然后load。如果是no，用戶必須手動redis-check-aof修復AOF文件才可以。默認值為 yes。 aof-load-truncated yes # 開啟混合持久化 # redis保證RDB轉儲跟AOF重寫不會同時進行。 # 當redis啟動時，即便RDB和AOF持久化同時啟用且AOF，RDB文件都存在，則redis總是會先加載AOF文件，這是因為AOF文件被認為能夠更好的保證數據一致性， # 當加載AOF文件時，如果啟用了混合持久化，那么redis將首先檢查AOF文件的前綴，如果前綴字符是REDIS，那么該AOF文件就是混合格式的，redis服務器會先加載RDB部分，然后再加載AOF部分。 aof-use-rdb-preamble yes ################################ LUA SCRIPTING ############################### # Lua腳本執行超時時間 # # 設置成0或者負值表示不限時 lua-time-limit 5000 ################################ REDIS CLUSTER ############################### # # 開啟集群功能，此redis實例作為集群的一個節點 # # cluster-enabled yes # 集群配置文件 # 此配置文件不能人工編輯，它是集群節點自動維護的文件，主要用於記錄集群中有哪些節點、他們的狀態以及一些持久化參數等，方便在重啟時恢復這些狀態。通常是在收到請求之后這個文件就會被更新 # cluster-config-file nodes-6379.conf # 集群中的節點能夠失聯的最大時間，超過這個時間，該節點就會被認為故障。如果主節點超過這個時間還是不可達，則用它的從節點將啟動故障遷移，升級成主節點 # # cluster-node-timeout 15000 # 如果設置成０，則無論從節點與主節點失聯多久，從節點都會嘗試升級成主節點。 # 如果設置成正數，則cluster-node-timeout*cluster-slave-validity-factor得到的時間，是從節點與主節點失聯后， # 此從節點數據有效的最長時間，超過這個時間，從節點不會啟動故障遷移。 # 假設cluster-node-timeout=5，cluster-slave-validity-factor=10，則如果從節點跟主節點失聯超過50秒，此從節點不能成為主節點。 # 注意，如果此參數配置為非0，將可能出現由於某主節點失聯卻沒有從節點能頂上的情況，從而導致集群不能正常工作， # 在這種情況下，只有等到原來的主節點重新回歸到集群，集群才恢復運作。 # # cluster-replica-validity-factor 10 # 主節點需要的最小從節點數，只有達到這個數，主節點失敗時，從節點才會進行遷移。 # # cluster-migration-barrier 1 # 在部分key所在的節點不可用時，如果此參數設置為"yes"(默認值), 則整個集群停止接受操作； # 如果此參數設置為”no”，則集群依然為可達節點上的key提供讀操作。 # # cluster-require-full-coverage yes # 在主節點失效期間,從節點不允許對master失效轉移 # cluster-replica-no-failover no ########################## CLUSTER DOCKER/NAT support ######################## #默認情況下，Redis會自動檢測自己的IP和從配置中獲取綁定的PORT，告訴客戶端或者是其他節點。 #而在Docker環境中，如果使用的不是host網絡模式，在容器內部的IP和PORT都是隔離的，那么客戶端和其他節點無法通過節點公布的IP和PORT建立連接。 #如果開啟以下配置，Redis節點會將配置中的這些IP和PORT告知客戶端或其他節點。而這些IP和PORT是通過Docker轉發到容器內的臨時IP和PORT的。 # # Example: # # cluster-announce-ip 10.1.1.5 # cluster-announce-port 6379 # cluster-announce-bus-port 6380 ################################## SLOW LOG ################################### # 執行時間大於slowlog-log-slower-than的才會定義成慢查詢，才會被slow-log記錄 # 這里的單位是微秒，默認是 10ms slowlog-log-slower-than 10000 # 慢查詢最大的條數，當slowlog超過設定的最大值后，會將最早的slowlog刪除，是個FIFO隊列 slowlog-max-len 128 ################################ LATENCY MONITOR ############################## # Redis延遲監視子系統在運行時對不同的操作進行采樣，以便收集可能導致延時的數據根源。 # # 通過LATENCY命令，可以打印圖表並獲取報告。 # # 系統僅記錄在等於或大於 latency-monitor-threshold 指定的毫秒數的時間內執行的操作。 當其值設置為0時，將關閉延遲監視器。 # # 默認情況下，延遲監視被禁用，因為如果您沒有延遲問題，則通常不需要延遲監視，並且收集數據會對性能產生影響，雖然非常小。 # 如果需要，可以使用命令“CONFIG SET latency-monitor-threshold <milliseconds>”在運行時輕松啟用延遲監視。 latency-monitor-threshold 0 ############################# EVENT NOTIFICATION ############################## # Redis可以向Pub / Sub客戶端通知鍵空間發生的事件。 # # 例如，如果啟用了鍵空間事件通知，並且客戶端對存儲在數據庫0中的鍵 foo 執行DEL操作，則將通過Pub / Sub發布兩條消息: # # PUBLISH __keyspace@0__:foo del # PUBLISH __keyevent@0__:del foo # 以 keyspace 為前綴的頻道被稱為鍵空間通知（key-space notification）， 而以 keyevent 為前綴的頻道則被稱為鍵事件通知（key-event notification）。 # 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 鍵空間通知，所有通知以 __keyspace@<db>__ 為前綴. # E 鍵事件通知，所有通知以 __keyevent@<db>__ 為前綴 # g DEL 、 EXPIRE 、 RENAME 等類型無關的通用命令的通知 # $ 字符串命令的通知 # l 列表命令的通知 # s 集合命令的通知 # h 哈希命令的通知 # z 有序集合命令的通知 # x 過期事件：每當有過期鍵被刪除時發送 # e 驅逐(evict)事件：每當有鍵因為 maxmemory 策略而被刪除時發送 # A 參數 g$lshzxe 的別名 # # 輸入的參數中至少要有一個 K 或者 E ， 否則的話， 不管其余的參數是什么， 都不會有任何通知被分發。 # 如果只想訂閱鍵空間中和列表相關的通知， 那么參數就應該設為 Kl。將參數設為字符串 "AKE" 表示發送所有類型的通知。 notify-keyspace-events "" ############################### ADVANCED CONFIG ############################### # hash類型的數據結構在編碼上可以使用ziplist和hashtable。 # ziplist的特點就是文件存儲(以及內存存儲)所需的空間較小,在內容較小時,性能和hashtable幾乎一樣。 # 因此redis對hash類型默認采取ziplist。如果hash中條目個數或者value長度達到閥值,內部編碼將使用hashtable。 # 這個參數指的是ziplist中允許存儲的最大條目個數，默認為512，建議為128 hash-max-ziplist-entries 512 # ziplist中允許條目value值最大字節數，默認為64，建議為1024 hash-max-ziplist-value 64 # 當取正值的時候，表示按照數據項個數來限定每個quicklist節點上的ziplist長度。比如，當這個參數配置成5的時候，表示每個quicklist節點的ziplist最多包含5個數據項。 # 當取負值的時候，表示按照占用字節數來限定每個quicklist節點上的ziplist長度。這時，它只能取-1到-5這五個值 # -5: max size: 64 Kb <-- not recommended for normal workloads # -4: max size: 32 Kb <-- not recommended # -3: max size: 16 Kb <-- probably not recommended # -2: max size: 8 Kb <-- good # -1: max size: 4 Kb <-- good # 性能最高的選項通常為-2（8 Kb大小）或-1（4 Kb大小）。 list-max-ziplist-size -2 # 一個quicklist兩端不被壓縮的節點個數 # 參數list-compress-depth的取值含義如下： # 0: 表示都不壓縮。這是Redis的默認值 # 1: 表示quicklist兩端各有1個節點不壓縮，中間的節點壓縮。 # So: [head]->node->node->...->node->[tail] # [head], [tail] 不壓縮; 內部節點將被壓縮. # 2: [head]->[next]->node->node->...->node->[prev]->[tail] # 2：表示quicklist兩端各有2個節點不壓縮，中間的節點壓縮 # 3: [head]->[next]->[next]->node->node->...->node->[prev]->[prev]->[tail] # 3: 表示quicklist兩端各有3個節點不壓縮，中間的節點壓縮。 # etc. list-compress-depth 0 # 數據量小於等於512用intset，大於512用set set-max-intset-entries 512 # 數據量小於等於zset-max-ziplist-entries用ziplist，大於zset-max-ziplist-entries用zset zset-max-ziplist-entries 128 zset-max-ziplist-value 64 # value大小小於等於hll-sparse-max-bytes使用稀疏數據結構（sparse） # 大於hll-sparse-max-bytes使用稠密的數據結構（dense），一個比16000大的value是幾乎沒用的， # 建議的value大概為3000。如果對CPU要求不高，對空間要求較高的，建議設置到10000左右 hll-sparse-max-bytes 3000 #Streams宏節點最大大小。流數據結構是基數編碼內部多個項目的大節點樹。使用此配置 #可以配置單個節點的字節數，以及切換到新節點之前可能包含的最大項目數 #追加新的流條目。如果以下任何設置設置為0，忽略限制，因此例如可以設置一個 #大入口限制將max-bytes設置為0，將max-entries設置為所需的值 stream-node-max-bytes 4096 stream-node-max-entries 100 # 主動重新散列每100毫秒CPU時間使用1毫秒，以幫助重新散列主Redis散列表（將頂級鍵映射到值）。 # Redis使用的散列表實現（請參閱dict.c）執行延遲重新散列：您在重新散列的散列表中運行的操作越多，執行的重復“步驟”就越多， # 因此如果服務器處於空閑狀態，則重新散列將永遠不會完成 哈希表使用了一些內存。 activerehashing yes # 對客戶端輸出緩沖進行限制可以強迫那些不從服務器讀取數據的客戶端斷開連接，用來強制關閉傳輸緩慢的客戶端。 # 對於normal client，第一個0表示取消hard limit，第二個0和第三個0表示取消soft limit，normal client默認取消限制 client-output-buffer-limit normal 0 0 0 # 對於slave client和MONITER client，如果client-output-buffer一旦超過256mb，又或者超過64mb持續60秒，那么服務器就會立即斷開客戶端連接。 client-output-buffer-limit replica 256mb 64mb 60 # 對於pubsub client，如果client-output-buffer一旦超過32mb，又或者超過8mb持續60秒，那么服務器就會立即斷開客戶端連接。 client-output-buffer-limit pubsub 32mb 8mb 60 # 客戶端查詢緩沖區累積新命令。 默認情況下，它被限制為固定數量，以避免協議失步（例如由於客戶端中的錯誤）將導致查詢緩沖區中的未綁定內存使用。 # 但是，如果您有非常特殊的需求，可以在此配置它，例如我們巨大執行請求。 # # client-query-buffer-limit 1gb # 在Redis協議中，批量請求（即表示單個字符串的元素）通常限制為512 MB。 但是，您可以在此更改此限制。 # # proto-max-bulk-len 512mb # Redis調用內部函數來執行許多后台任務，例如在超時時關閉客戶端的連接，清除從未請求過期的過期密鑰等等。 # # 並非所有任務都以相同的頻率執行，但Redis會根據指定的“hz”值檢查要執行的任務。 # # 默認情況下，hz設置為10.提高值時，在Redis處於空閑狀態下，將使用更多CPU # 但同時，當有很多鍵同時到期時，Redis會響應更快，並且可以更精確地處理超時。 # # 范圍介於1到500之間，但超過100的值通常不是一個好主意。 大多數用戶應使用默認值10，除非僅在需要非常低延遲的環境中將此值提高到100。 hz 10 # 通常，推薦使HZ的值與連接的客戶端數量成比例。這有助於避免為每個后台任務調用處理太多客戶端，以避免延遲峰值。 # # 默認情況下默認的HZ值為10。Redis 提供並啟用自適應HZ值的功能，當有很多連接的客戶端時，該值會臨時增加。 # # 啟用動態HZ時，實際配置的HZ將用作基線，但是一旦連接了更多客戶端，將根據實際需要使用配置的HZ值的倍數。 # 通過這種方式，空閑實例將使用非常少的CPU時間，而繁忙的實例將更具響應性。 dynamic-hz yes # 當一個子進程重寫AOF文件時，如果啟用下面的選項，則文件每生成32M數據會被同步。 aof-rewrite-incremental-fsync yes # 當redis保存RDB文件時，如果啟用了以下選項，則每生成32 MB數據將對文件進行fsync。 這對於以遞增方式將文件提交到磁盤並避免大延遲峰值非常有用。 rdb-save-incremental-fsync yes # 可以調整Redis LFU（參見maxmemory設置）。 但是，最好使用默認設置，僅在調查如何改進性能以及LFU如何隨時間變化后更改它們，這可以通過OBJECT FREQ命令進行檢查。 # # Redis LFU實現中有兩個可調參數：計數器對數因子和計數器衰減時間。 在更改它們之前，了解這兩個參數的含義非常重要。 # # LFU計數器每個鍵只有8位，它的最大值是255，因此Redis使用具有對數行為的概率增量。 給定舊計數器的值，當訪問密鑰時，計數器以這種方式遞增： # # 1. A random number R between 0 and 1 is extracted. # 2. A probability P is calculated as 1/(old_value*lfu_log_factor+1). # 3. The counter is incremented only if R < P. # # The default lfu-log-factor is 10. This is a table of how the frequency # counter changes with a different number of accesses with different # logarithmic factors: # # +--------+------------+------------+------------+------------+------------+ # | factor | 100 hits | 1000 hits | 100K hits | 1M hits | 10M hits | # +--------+------------+------------+------------+------------+------------+ # | 0 | 104 | 255 | 255 | 255 | 255 | # +--------+------------+------------+------------+------------+------------+ # | 1 | 18 | 49 | 255 | 255 | 255 | # +--------+------------+------------+------------+------------+------------+ # | 10 | 10 | 18 | 142 | 255 | 255 | # +--------+------------+------------+------------+------------+------------+ # | 100 | 8 | 11 | 49 | 143 | 255 | # +--------+------------+------------+------------+------------+------------+ # # NOTE: The above table was obtained by running the following commands: # # redis-benchmark -n 1000000 incr foo # redis-cli object freq foo # # NOTE 2: The counter initial value is 5 in order to give new objects a chance # to accumulate hits. # # The counter decay time is the time, in minutes, that must elapse in order # for the key counter to be divided by two (or decremented if it has a value # less <= 10). # # The default value for the lfu-decay-time is 1. A Special value of 0 means to # decay the counter every time it happens to be scanned. # # lfu-log-factor 10 # lfu-decay-time 1 ########################### ACTIVE DEFRAGMENTATION ####################### # # WARNING THIS FEATURE IS EXPERIMENTAL. However it was stress tested # even in production and manually tested by multiple engineers for some # time. # # What is active defragmentation? # ------------------------------- # # Active (online) defragmentation allows a Redis server to compact the # spaces left between small allocations and deallocations of data in memory, # thus allowing to reclaim back memory. # # Fragmentation is a natural process that happens with every allocator (but # less so with Jemalloc, fortunately) and certain workloads. Normally a server # restart is needed in order to lower the fragmentation, or at least to flush # away all the data and create it again. However thanks to this feature # implemented by Oran Agra for Redis 4.0 this process can happen at runtime # in an "hot" way, while the server is running. # # Basically when the fragmentation is over a certain level (see the # configuration options below) Redis will start to create new copies of the # values in contiguous memory regions by exploiting certain specific Jemalloc # features (in order to understand if an allocation is causing fragmentation # and to allocate it in a better place), and at the same time, will release the # old copies of the data. This process, repeated incrementally for all the keys # will cause the fragmentation to drop back to normal values. # # Important things to understand: # # 1. This feature is disabled by default, and only works if you compiled Redis # to use the copy of Jemalloc we ship with the source code of Redis. # This is the default with Linux builds. # # 2. You never need to enable this feature if you don't have fragmentation # issues. # # 3. Once you experience fragmentation, you can enable this feature when # needed with the command "CONFIG SET activedefrag yes". # # The configuration parameters are able to fine tune the behavior of the # defragmentation process. If you are not sure about what they mean it is # a good idea to leave the defaults untouched. # 啟用主動碎片整理 # activedefrag yes # 啟動活動碎片整理的最小碎片浪費量 # active-defrag-ignore-bytes 100mb # 啟動碎片整理的最小碎片百分比 # active-defrag-threshold-lower 10 # 使用最大消耗時的最大碎片百分比 # active-defrag-threshold-upper 100 # 在CPU百分比中進行碎片整理的最小消耗 # active-defrag-cycle-min 5 # 在CPU百分比達到最大值時，進行碎片整理 # active-defrag-cycle-max 75 # 從set / hash / zset / list 掃描的最大字段數 # active-defrag-max-scan-fields 1000
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- 作 者 : Yaopengfei(姚鵬飛)
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