docker搭建redis三主三从集群

  • 一 准备redis镜像、容器
    • 1.1 下载redis6.0.8
    • 1.2 准备6台服务器配置文件
    • 1.3 创建6台redis容器
  • 二 创建主从集群关系
    • 2.1 进入任意一台redis容器
    • 2.2 构建主从关系
    • 2.3 查看集群状态
  • 三 主从容错切换迁移案例
    • 3.1 数据读写存储
      • 3.1.1 进入6381新增两组key
      • 3.1.2 切换到集群上的其他服务器，获取值
      • 3.1.3 查看集群信息
    • 3.2 容错切换迁移
      • 3.2.1 主6381和从机切换
      • 3.2.2 重启6381
      • 3.2.3 查看集群状态
  • 四 主从扩容
    • 4.1 新建6387、6388两个节点+新建后启动+查看是否8节点
    • 4.2 进入6387容器实例内部
    • 4.3 将新增的6387节点(空槽号)作为master节点加入原集群
    • 4.5 检查集群情况第1次
    • 4.6 重新分派槽号
    • 4.7 检查集群情况第2次
    • 4.8 为主节点6387分配从节点6388
    • 4.9 第三次查看集群情况
  • 四 主从缩容案例
    • 4.1 检查集群情况并获得6388的节点ID
    • 4.2 将6388删除（从集群中将4号从节点6388删除）
    • 4.3 将6387的槽号清空，重新分配，本例将清出来的槽号都给6381
    • 4.4 检查集群情况第二次
    • 4.5 将6387删除
    • 4.6 检查集群情况第三次
  • 附： redis出厂配置文件

一 准备redis镜像、容器

1.1 下载redis6.0.8

docker pull redis:6.0.8

1.2 准备6台服务器配置文件

# redis出场配置放在文章最后mkdir -p /usr/local/repository/redis/redis-node-1# 配置参考文章最后vim /usr/local/repository/redis/redis-node-1/redis.conf cd /usr/local/repository/redis# 依次复制其他5份cp -r redis-node-1/ ./redis-node-2

1.3 创建6台redis容器

docker run -d --name redis-node-1 --net host --privileged=true -v /usr/local/repository/redis/redis-node-1/redis.conf:/etc/redis/redis.conf -v /usr/local/repository/redis/redis-node-1/data:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6381 docker run -d --name redis-node-2 --net host --privileged=true -v /usr/local/repository/redis/redis-node-2/redis.conf:/etc/redis/redis.conf -v /usr/local/repository/redis/redis-node-2/data:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6382docker run -d --name redis-node-3 --net host --privileged=true -v /usr/local/repository/redis/redis-node-3/redis.conf:/etc/redis/redis.conf -v /usr/local/repository/redis/redis-node-3/data:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6383docker run -d --name redis-node-4 --net host --privileged=true -v /usr/local/repository/redis/redis-node-4/redis.conf:/etc/redis/redis.conf -v /usr/local/repository/redis/redis-node-4/data:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6384docker run -d --name redis-node-5 --net host --privileged=true -v /usr/local/repository/redis/redis-node-5/redis.conf:/etc/redis/redis.conf -v /usr/local/repository/redis/redis-node-5/data:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6385docker run -d --name redis-node-6 --net host --privileged=true -v /usr/local/repository/redis/redis-node-6/redis.conf:/etc/redis/redis.conf -v /usr/local/repository/redis/redis-node-6/data:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6386

二 创建主从集群关系

2.1 进入任意一台redis容器

docker exec -it redis-node-1 /bin/bash

2.2 构建主从关系

redis-cli --cluster create 192.168.202.200:6381 192.168.202.200:6382 192.168.202.200:6383 192.168.202.200:6384 192.168.202.200:6385 192.168.202.200:6386 --cluster-replicas 1# --cluster-replicas 1 表示为每个master创建一个slave节点

2.3 查看集群状态

# 进入任意redis容器，这里以6381为例redis-cli -p 6381cluster infocluster nodes

三 主从容错切换迁移案例

3.1 数据读写存储

3.1.1 进入6381新增两组key

# 重新进入6381，-c可以防止路由失效（(error) MOVED 12706 192.168.202.200:6383），往其他服务器hash槽存数据时报错。redis-cli -p 6381 -cset k1 v1set k2 v2

3.1.2 切换到集群上的其他服务器，获取值

3.1.3 查看集群信息

3.2 容错切换迁移

3.2.1 主6381和从机切换

# 停止6381，机器，查看集群状态docker stop redis-node-1# 进入6382容器，查看集群状态docker exec -it redis-node-2 bash
# 进入容器后先进入redisredis-cli -p 6382 -c# 查看集群信息cluster nodes


上图可以看出，当6381宕机后，6384由从机变为了主机。

3.2.2 重启6381

重启之后发现，6381还是从机，6384是主机。人走茶凉。要变回来只要把6384停了再启动即可。

# 先启动6381，再重启6384，即可将6381变为主机器。这里不做测试。docker stop redis-node-4docker start redis-node-4

3.2.3 查看集群状态

redis-cli --cluster check 自己IP:6381

四 主从扩容

4.1 新建6387、6388两个节点+新建后启动+查看是否8节点

# 到宿主机上，准备配置文件cd /usr/local/repository/redis# 参考上面6台机器，生成配置文件# 启动6387及6388两个容器docker run -d --name redis-node-7 --net host --privileged=true -v /usr/local/repository/redis/redis-node-7/redis.conf:/etc/redis/redis.conf -v /usr/local/repository/redis/redis-node-7/data:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6387docker run -d --name redis-node-8 --net host --privileged=true -v /usr/local/repository/redis/redis-node-8/redis.conf:/etc/redis/redis.conf -v /usr/local/repository/redis/redis-node-8/data:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6388# 查看容器是否创建成功docker ps

4.2 进入6387容器实例内部

docker exec -it redis-node-7 /bin/bash

4.3 将新增的6387节点(空槽号)作为master节点加入原集群

# 将新增的6387作为master节点加入集群redis-cli --cluster add-node 自己实际IP地址:6387 自己实际IP地址:63816387 就是将要作为master新增节点6381 就是原来集群节点里面的领路人，相当于6387拜拜6381的码头从而找到组织加入集群

4.5 检查集群情况第1次

redis-cli --cluster check 真实ip地址:6381# 执行结果可以看出暂时没有槽号

4.6 重新分派槽号

# 重新分派槽号# 命令:redis-cli --cluster reshard IP地址:端口号redis-cli --cluster reshard 192.168.202.200:6381# 4096 下面的是接收hash槽的redis容器ID，这里是6387对应的id# source node :从哪些原来的主机上分配资源下来，all表示全部master


4.7 检查集群情况第2次

redis-cli --cluster check 真实ip地址:6381
# 槽号分派说明为什么6387是3个新的区间，以前的还是连续？重新分配成本太高，所以前3家各自匀出来一部分，从6381/6382/6383三个旧节点分别匀出1364个坑位给新节点6387

4.8 为主节点6387分配从节点6388

命令：redis-cli --cluster add-node ip:新slave端口 ip:新master端口 --cluster-slave --cluster-master-id 新主机节点ID redis-cli --cluster add-node 192.168.202.200:6388 192.168.202.200:6387 --cluster-slave --cluster-master-id e4781f644d4a4e4d4b4d107157b9ba8144631451-------这个是6387的编号，按照自己实际情况

4.9 第三次查看集群情况

redis-cli --cluster check 192.168.202.200:6382

四 主从缩容案例

4.1 检查集群情况并获得6388的节点ID

redis-cli --cluster check 192.168.202.200:6382

4.2 将6388删除（从集群中将4号从节点6388删除）

# 命令：redis-cli --cluster del-node ip:从机端口 从机6388节点IDredis-cli --cluster del-node 192.168.202.200:6388 6388节点redis容器ID

4.3 将6387的槽号清空，重新分配，本例将清出来的槽号都给6381

redis-cli --cluster reshard 192.168.202.200:6381

4.4 检查集群情况第二次

# 4096个槽位都指给6381，它变成了8192个槽位，相当于全部都给6381了# 如果想平均分配的话可以多次分配，每次分配指定hash槽数redis-cli --cluster check 192.168.202.200:6381

4.5 将6387删除

# 命令：redis-cli --cluster del-node ip:端口 6387节点ID redis-cli --cluster del-node 192.168.202.200:6387 ce1263dbe9e034e99fea8359f0177dde57ea6367

4.6 检查集群情况第三次

# 又变回了三主三从，6384hash槽是8192redis-cli --cluster check 192.168.202.200:6381

附： redis出厂配置文件

# 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 no # 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/nulllogfile "" # 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  where# dbid is a number between 0 and 'databases'-1databases 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  ##   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 1save 300 10save 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" /># 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  # 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  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  # 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 nolazyfree-lazy-expire nolazyfree-lazy-server-del noreplica-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 alwaysappendfsync 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 100auto-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  ############################### # 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 " 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@__ prefix.#  E     Keyevent events, published with __keyevent@__ 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 512hash-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 128zset-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 4096stream-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    ## 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 0client-output-buffer-limit replica 256mb 64mb 60client-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