Redis之配置文件redis.conf

时间：2021-07-25 16:23:48

解读下 redis.conf 配置文件中常用的配置项，为不显得过于臃长，已选择性删除原配置文件中部分注释。

# Redis must be started with the file path as first argument:

# ./redis-server /path/to/redis.conf

## redis中的度量单位只支持bytes，不支持bit，大小写不敏感，且 k/kb、m/mb、g/gb 代表的单位大小有所不同。

# 1k => 1000 bytes

# 1kb => 1024 bytes

# 1m => 1000000 bytes

# 1mb => 1024*1024 bytes

# 1g => 1000000000 bytes

# 1gb => 1024*1024*1024 bytes

################################## INCLUDES ###################################

# 用于引入其他配置文件，和本配置文件中配置共同配置redis服务

# 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

# 服务启动端口，默认为 6379 ，如果设置端口为 0 ，redis 服务将不会监听任何TCP连接

port 

# 设置TCP的连接队列 backlog ，默认为 511 ，backlog 队列总和 = 未完成三次握手队列 + 已完成三次握手队列

# 作用：在高并发环境中，设置高 backlog 值，来避免慢客户端的连接
# 设置方式：（1）设置 /proc/sys/net/core/somaxconn （2）设置 tcp_max_syn_backlog
# Linux内核会将 tcp_max_syn_backlog 的值减小到 somaxconn ，故需要同时设置
# tcp_max_syn_backlog 1024 
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

# 当客户端超过N秒空闲后，服务器主动断开连接，设置为 0 表示不主动断开连接

timeout 

# 检测 TCP 连接alive状态的频率，设置为0表示不检测，建议设置为60

tcp-keepalive 

################################# GENERAL #####################################

# 设置redis服务以后台守护进程启动，默认为 no非daemon

# 后台启动后服务的 pid 位于文件 /var/run/redis 中

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

# 设置输出日志级别，包括 debug、verbos、notice、warning

loglevel notice

# 设置日志输出文件，若为空字符串"" 或者 stdout ，则将日志从定位到 /dev/null

logfile ""

# 若要将redis日志记录到系统日志，将此参数设置为 yes

# syslog-enabled no

# 用于指定日志标识：若开启系统日志，指定日志以 redis 开头

# syslog-ident redis

# 设置系统日志输出设备，值可为 USER 或者 LOCAL0-LOCAL7，默认为local0

# syslog-facility local0

# 设置 redis 服务启动数据库的个数，默认 16 个，默认数据库为 DB 0 ，可使用 select <dbid> 进行切库，dbid为 0 至 databases-1

databases 

# 是否总是显示redis那个"蛋糕"logo

always-show-logo yes

################################ SNAPSHOTTING  ################################

# 指定在规定时间内，有多少此更新操作，就将数据同步至数据文件，可多个条件配合使用

#   save <seconds> <changes>

#　　save ""

# 默认配置如下：15分钟内有一个更改，5分钟内有10个更改，1分钟内有10000个更改

save  1

save

save  

# 当RDB在后台持久化出错后，是否依然进行数据库写操作，yes:停止写操作，no:继续写操作

stop-writes-on-bgsave-error yes

# 指定存储至本地数据库时是否压缩数据，默认为yes：使用压缩，redis采用LZF压缩算法，使用会消耗CPU，不使用占内存

rdbcompression yes

# 是否校验压缩后的rdb文件，默认为yes：进行校验，开启大概有10%性能损耗

rdbchecksum yes

# 指定本地数据库文件名，默认为dump.rdb

dbfilename dump.rdb

# 指定本地数据文件存放目录

dir ./

################################# REPLICATION #################################

# 将当前服务器作为从库，同步备份主库的数据，并提供读操作

# replicaof <masterip> <masterport>
# replicaof 10.7.5.74 6379

# 当master服务设置了密码保护时，slave服务连接master的密码

# 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 

# 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 

# 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 ###################################

# 登录 redis 数据库密码认证问题
# 执行命令 config get requirepass ，获取配置文件中默认认证密码，默认密码为 foobared

# requirepass foobared

# 执行命令 config set requirepass "redis" ，设置认证密码为 redis ，设置为空 "" 表示不认证
# 在执行命令前使用 auth <password> 命令进行认证

# 禁止远程修改 DB 文件地址，就是对命令进行权限控制

# 将命令重命名为空 ""，表示禁用该命令

# rename-command FLASHALL ""

# 也可将命令重命名为 qazwsx741852edc ，然后将此名授权给特定用户使用即可
# rename-command CONFIG "qazwsx741852edc"
################################### CLIENTS ####################################

# 设置客户端默认最大连接数，设置为0表示不限制，默认为10000

# maxclients 10000

############################## MEMORY MANAGEMENT ################################

# 设置 redis 最大内存容量

# maxmemory <bytes>

# 内存达到上限的处理策略（lru means Least Recently Used<最近最少>,lfu means Least Frequently Used<最不常>）

# volatile-lru -> 利用LRU算法移除设置过过期时间的key

# allkeys-lru -> 利用LRU算法移除任何key

# volatile-lfu -> 利用LFU算法移除设置过过期时间的key

# allkeys-lfu -> 利用LFU算法移除任何key

# volatile-random -> 随机移除设置过过期时间的key

# allkeys-random -> 随机移除所有key

# volatile-ttl -> 移除即将过期的key

# noeviction -> 不移除key，返回报错就行

# 默认为不移除key策略

# maxmemory-policy noeviction

# 设置每次移除时的样本大小，默认5个：每次移除时选取5个样本，移除其中符合策略的key

# maxmemory-samples 5

# 从节点是否忽略maxmemory设置的值

# 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 ###############################

# 指定是否在每次更新操作后进行日志记录，redis默认异步将数据写入磁盘，不开启会导致断电时一段时间内的数据丢失，默认no

appendonly no

# 指定更新日志文件名，默认为appendonly.aof

appendfilename "appendonly.aof"

# 指定更新日志条件，建议使用 "everysec"

# "always"：同步持久化，每次发生数据更改会立即调用fsync()方法将数据写入磁盘，数据完整性好，性能差
# "everysec"：默认值，异步同步，每秒同步一次，若一秒内宕机，则存在数据丢失
# "no"：永不

# appendfsync always

appendfsync everysec

# appendfsync no

# 重写时，是否可以使用appendfsync（接受客户端的写操作），默认为 no ，保证数据安全性

no-appendfsync-on-rewrite no

# redis会记录上次重写AOF文件的大小，当AOF文件增加至上次重写文件的 100% 倍，且大小大于64MB时，触发AOF重写
# auto-aof-rewrite-percentage 用于设置相对于上次AOF文件百分比，auto-aof-rewrite-min-size 用于设置另一基准值

auto-aof-rewrite-percentage

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 

################################ 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 

# 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 

################################ 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 

############################# 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 ###############################

# 指定在超过一定数据或者最大的元素超过某一临界值时，采用如下特殊哈希算法，未超过则使用ziplist

hash-max-ziplist-entries

hash-max-ziplist-value 

# 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 -

# 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 

# 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 

# 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

zset-max-ziplist-value 

# 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 

# 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

stream-node-max-entries 

# 指定是否激活重置哈希，默认为开启。对实时性要求高的，可更改为no，不开启

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

client-output-buffer-limit replica 256mb 64mb

client-output-buffer-limit pubsub 32mb 8mb 

# 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 

# 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

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