redis应用之安装配置介绍

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#cat redis.conf　　
# 当你需要为某个配置项指定内存大小的时候，必须要带上单位，通常的格式就是 1k 5gb 4m 等这样
　　
# 1k  => 1000 bytes
　　
# 1kb => 1024 bytes
　　
# 1m  => 1000000 bytes
　　
# 1mb => 1024*1024 bytes
　　
# 1g  => 1000000000 bytes
　　
# 1gb => 1024*1024*1024 bytes
　　
# 单位是不区分大小写的，你写 1K 5GB 4M 也行
　　
# 假如说你有一个可用于所有的 redis server 的标准配置模板，
　　
# 但针对某些 server 又需要一些个性化的设置，
　　
# 你可以使用 include 来包含一些其他的配置文件，这对你来说是非常有用的。
　　
# 但是要注意，include 是不能被 config rewrite 命令改写的
　　
# 由于 redis 总是以最后的加工线作为一个配置指令值，所以你最好是把 include 放在这个文件的最前面，
　　
# 以避免在运行时覆盖配置的改变，相反，你就把它放在后面。
　　
# include /path/to/local.conf
　　
# include /path/to/other.conf
　　
################################ 常用 #####################################
　　
# 默认情况下 redis 不是作为守护进程运行的，如果你想让它在后台运行，你就把它改成 yes。
　　
daemonize no
　　
# 当redis作为守护进程运行的时候，它会把 pid 默认写到 /var/run/redis.pid 文件里面，
　　
# 但是你可以在这里自定义它的文件位置。
　　
pidfile /var/run/redis.pid
　　
# 监听端口号，默认为 6379，如果你设为0,redis 将不在 socket 上监听任何客户端连接，也可以自定义端口
　　
port 6379
　　
# TCP 监听的最大容纳数量
　　
# 在高并发的环境下，你需要把这个值调高以避免客户端连接缓慢的问题。
　　
# Linux 内核会一声不响的把这个值缩小成 /proc/sys/net/core/somaxconn 对应的值，
　　
# 所以你要修改somaxconn和tcp_max_syn_backlog这两个值才能达到你的预期。
　　
tcp-backlog 511
　　
# 默认情况下，redis 在 server 上所有有效的网络接口上监听客户端连接。
　　
# 你如果只想让它在一个网络接口上监听，那你就绑定一个IP或者多个IP。
　　
# 示例，多个IP用空格隔开:
　　
# bind 192.168.1.100 10.0.0.1
　　
# bind 127.0.0.1
　　
# 指定 unix socket 的路径。
　　
# unixsocket /tmp/redis.sock
　　
# unixsocketperm 755
　　
# 指定在一个 client 空闲多少秒之后关闭连接（0 就是不管它）
　　
timeout 0
　　
# tcp 心跳包。
　　
# 如果设置为非零，则在与客户端缺乏通讯的时候使用SO_KEEPALIVE发送tcp acks给客户端。
　　
# 这个之所有有用，主要由两个原因：
　　
# 1) 防止死的 peers
　　
# 2) Take the connection alive from the point of view of network
　　
#    equipment in the middle.
　　
# On Linux, the specified value (in seconds) is the period used to send ACKs.
　　
# Note that to close the connection the double of the time is needed.
　　
# On other kernels the period depends on the kernel configuration.
　　
#
　　
# A reasonable value for this option is 60 seconds.
　　
# 推荐一个合理的值就是60秒
　　
tcp-keepalive 0
　　
# 定义日志级别。
　　
# 可以是下面的这些值：
　　
# debug (适用于开发或测试阶段)
　　
# verbose (many rarely useful info, but not a mess like the debug level)
　　
# notice (适用于生产环境)
　　
# warning (仅仅一些重要的消息被记录)
　　
loglevel notice
　　
# 指定日志文件的位置
　　
logfile "/var/log/redis.log"
　　
# 要想把日志记录到系统日志，就把它改成 yes，
　　
# 也可以可选择性的更新其他的syslog 参数以达到你的要求
　　
# syslog-enabled no
　　
# 设置 syslog 的 identity。
　　
# syslog-ident redis
　　
# 设置 syslog 的 facility，必须是 USER 或者是 LOCAL0-LOCAL7 之间的值。
　　
# syslog-facility local0
　　
# 设置数据库的数目。
　　
# 默认数据库是 DB 0，你可以在每个连接上使用 select  命令选择一个不同的数据库，
　　
# 但是 db id 必须是一个介于 0 到 databasees - 1 之间的值
　　
databases 16
　　
################################ 快照 ################################
　　
#
　　
# 存 DB 到磁盘：
　　
#
　　
#   格式：save  
　　
#
　　
#   根据给定的时间间隔和写入次数将数据保存到磁盘
　　
#
　　
#   下面的例子的意思是：
　　
#   900 秒内如果至少有 1 个 key 的值变化，则保存
　　
#   300 秒内如果至少有 10 个 key 的值变化，则保存
　　
#   60 秒内如果至少有 10000 个 key 的值变化，则保存
　　
#　　
　　
#   注意：你可以注释掉所有的 save 行来停用保存功能。
　　
#   也可以直接一个空字符串来实现停用：
　　
#   save ""
　　
save 900 1
　　
save 300 10
　　
save 60 10000
　　
# 默认情况下，如果 redis 最后一次的后台保存失败，redis 将停止接受写操作，
　　
# 这样以一种强硬的方式让用户知道数据不能正确的持久化到磁盘，否则就会没人注意到灾难的发生。
　　
# 如果后台保存进程重新启动工作了，redis也将自动的允许写操作。
　　
补充：
　　
redis的存储分为内存存储、磁盘存储和log文件三部分，配置文件中有三个参数对其进行配置。
　　
因为redis本身同步数据文件是按上面的save条件来同步的，所以有的数据会在一段时间内只存在于内存中。开启的话每次写操作会记一条log，这会提高数据抗风险能力，但影响效率。
　　

　　
#然而如果你已经设置了对redis服务器的正确监视和持久性，你可能要禁用此功能，以便redis将继续正常工作
　　
即使有磁盘、权限等问题，说白点就是有任何问题导致的bgsave失败都停止redis的对外服务。默认yes，可以设置为no
　　
stop-writes-on-bgsave-error yes
　　
# 是否在dump .rdb 数据库的时候使用 LZF 压缩字符串，默认都设为 yes
　　
# 如果你希望保存子进程节省点 cpu ，你就设置它为 no，不过这个数据集可能就会比较大
　　
rdbcompression yes
　　
# 是否校验rdb文件
　　
rdbchecksum yes
　　
# 设置dump的文件名
　　
dbfilename dump.rdb
　　
# 工作目录
　　
# 例如上面的 dbfilename 只指定了文件名，
　　
# 但是它会写入到这个目录下。这个配置项一定是个目录，而不能是文件名。
　　
dir ./    #可以自定义，比如dir /usr/local/redis/
　　
################################# 主从复制 #################################
　　
# 主从复制。使用slaveof来让一个redis实例成为另一个reids实例的副本。
　　
关于Redis复制的几个事情
　　
# 1)redis复制是异步的，但是如果它看起来没有与至少给定数量的slave连接，你可以将master配置为停止接受写入
　　
# 2)如果复制链接丢失相对较少的时间，Redis从服务器能够与主设备执行部分重新同步。
　　
# 你可能需要根据你的需要使用合理的值配置复制积压大小（请参阅此文件的下一部分）
　　
# 3)复制是自动的，不需要用户干预。网络分区后，从服务器自动尝试重新连接到主服务器并与其同步。
　　
#
　　
# 设置当本机为slave服务时，设置master服务的IP地址及端口，在Redis启动时，它会自动从master进行数据同步
　　
# slaveof  
　　
# 如果 master 需要密码认证，就在这里设置
　　
# masterauth
　　
# 当一个 slave 与 master 失去联系，或者复制正在进行的时候，
　　
# slave 可能会有两种表现：
　　
# 1) 如果slave-serve-stale-data设置为 yes ，slave仍然会应答客户端请求，但返回的数据可能是过时，
　　
# 或者数据可能是空的在第一次同步的时候
　　
#
　　
# 2) 如果slave-serve-stale-data设置为 no ，在你执行除了info 和slaveof 之外的其他命令时，
　　
#    slave 都将返回一个 "SYNC with master in progress" 的错误，
　　
slave-serve-stale-data yes
　　
# 你可以配置一个slave实体是否接受写入操作。
　　
# 通过写入操作来存储一些短暂的数据对于一个 slave 实例来说可能是有用的，
　　
# 因为相对从 master 重新同步数而言，据数据写入到 slave 会更容易被删除。
　　
# 但是如果客户端因为一个错误的配置写入，也可能会导致一些问题。
　　
#
　　
# 从 redis 2.6 版起，默认 slaves 都是只读的。
　　
# Note: read only slaves are not designed to be exposed to untrusted clients
　　
# on the internet. It's just a protection layer against misuse of the instance.
　　
# Still a read only slave exports by default all the administrative commands
　　
# such as CONFIG, DEBUG, and so forth. To a limited extent you can improve
　　
# security of read only slaves using 'rename-command' to shadow all the
　　
# administrative / dangerous commands.
　　
# 注意：只读的 slaves 没有被设计成在 internet 上暴露给不受信任的客户端。
　　
# 它仅仅是一个针对误用实例的一个保护层。
　　
# 从服务器只读设置，默认是yes
　　
slave-read-only yes
　　
# 复制SYNC策略：磁盘或套接字。
　　
# 使用慢磁盘和快速（大带宽）网络，无盘复制的效果更好
　　
repl-diskless-sync no
　　
#当启用无磁盘复制时，可以配置服务器等待的延迟，以便生成将RDP通过套接字传输到从属设备的子节点。
　　
#
　　
#延迟时间以秒为单位，默认值为5秒。 要完全禁用它只是设置为0秒，传输将尽快启动。
　　
repl-diskless-sync-delay 5
　　
#
　　
# Slaves 在一个预定义的时间间隔内发送 ping 命令到 server 。
　　
# 你可以改变这个时间间隔。默认为 10 秒。
　　
# repl-ping-slave-period 10
　　
# The following option sets the replication timeout for:
　　
# 设置主从复制过期时间
　　
# 1) Bulk transfer I/O during SYNC, from the point of view of slave.
　　
# 2) Master timeout from the point of view of slaves (data, pings).
　　
# 3) Slave timeout from the point of view of masters (REPLCONF ACK pings).
　　
#
　　
# It is important to make sure that this value is greater than the value
　　
# specified for repl-ping-slave-period otherwise a timeout will be detected
　　
# every time there is low traffic between the master and the slave.
　　
# 这个值一定要比 repl-ping-slave-period 大
　　
#
　　
# repl-timeout 60
　　
# Disable TCP_NODELAY on the slave socket after SYNC?
　　
#
　　
# If you select "yes" Redis will use a smaller number of TCP packets and
　　
# less bandwidth to send data to slaves. But this can add a delay for
　　
# the data to appear on the slave side, up to 40 milliseconds with
　　
# Linux kernels using a default configuration.
　　
#
　　
# If you select "no" the delay for data to appear on the slave side will
　　
# be reduced but more bandwidth will be used for replication.
　　
#
　　
# By default we optimize for low latency, but in very high traffic conditions
　　
# or when the master and slaves are many hops away, turning this to "yes" may
　　
# be a good idea.
　　
默认情况下，我们针对低延迟进行优化，但在非常高的流量条件下或当主设备和从设备有许多跳时，
　　
将其转换为“yes”可能是一个好主意。所以默认是no
　　
repl-disable-tcp-nodelay no
　　
# 设置主从复制容量大小。这个 backlog 是一个用来在 slaves 被断开连接时
　　
# 存放 slave 数据的 buffer，所以当一个 slave 想要重新连接，通常不希望全部重新同步，
　　
# 只是部分同步就够了，仅仅传递 slave 在断开连接时丢失的这部分数据。
　　
#
　　
# The biggest the replication backlog, the longer the time the slave can be
　　
# disconnected and later be able to perform a partial resynchronization.
　　
# 这个值越大，salve 可以断开连接的时间就越长。
　　
#
　　
# The backlog is only allocated once there is at least a slave connected.
　　
#
　　
# repl-backlog-size 1mb
　　
# After a master has no longer connected slaves for some time, the backlog
　　
# will be freed. The following option configures the amount of seconds that
　　
# need to elapse, starting from the time the last slave disconnected, for
　　
# the backlog buffer to be freed.
　　
# 在某些时候，master 不再连接 slaves，backlog 将被释放。
　　
#
　　
# A value of 0 means to never release the backlog.
　　
# 如果设置为 0 ，意味着绝不释放 backlog 。
　　
#
　　
# repl-backlog-ttl 3600
　　
# The slave priority is an integer number published by Redis in the INFO output.
　　
# It is used by Redis Sentinel in order to select a slave to promote into a
　　
# master if the master is no longer working correctly.
　　
# 从属优先级是Redis在INFO输出中发布的整数。如果主服务器不再正确工作，则Redis Sentinel
　　
# 使用它来选择从服务器升级为主服务器。
　　
# A slave with a low priority number is considered better for promotion, so
　　
# for instance if there are three slaves with priority 10, 100, 25 Sentinel will
　　
# pick the one with priority 10, that is the lowest.
　　
# 具有低优先级号的从服务器被认为更好地用于推广，所以例如，如果存在具有优先级10,100,25的三个从服务器
　　
# 则哨兵将选择具有优先级10的那台，即最低的那个。
　　
# However a special priority of 0 marks the slave as not able to perform the
　　
# role of master, so a slave with priority of 0 will never be selected by
　　
# Redis Sentinel for promotion.
　　
# 当master不能正常工作的时候，Redis Sentinel 会从 slaves 中选出一个新的 master，
　　
# 这个值越小，就越会被优先选中，但是如果是 0 ，那是意味着这个 slave 不可能被选中。
　　
# 默认优先级为 100。
　　
slave-priority 100
　　
# It is possible for a master to stop accepting writes if there are less than
　　
# N slaves connected, having a lag less or equal than M seconds.
　　
# 如果连接少于N个slave服务器，具有小于或等于M秒的滞后，则master可以停止接受写入
　　
# The N slaves need to be in "online" state.
　　
# 这N个slave服务器必须是处于online状态
　　
# The lag in seconds, that must be  remove any key accordingly to the LRU algorithm
　　
# 根据 LRU 算法移除所有的 key 。
　　
# volatile-random -> remove a random key with an expire set
　　
# 删除带有过期集的随机密钥
　　
# allkeys-random -> remove a random key, any key
　　
# 移除一个随机key，任意key
　　
# volatile-ttl -> remove the key with the nearest expire time (minor TTL)
　　
# 删除具有最近过期时间的密钥（次TTL）
　　
# noeviction -> don't expire at all, just return an error on write operations
　　
# 不让任何 key 过期，只是在写入操作时返回一个错误
　　
#
　　
# Note: with any of the above policies, Redis will return an error on write
　　
#       operations, when there are not suitable keys for eviction.
　　
#
　　
#       At the date of writing this commands are: set setnx setex append
　　
#       incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd
　　
#       sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby
　　
#       zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby
　　
#       getset mset msetnx exec sort
　　
#
　　
# The default is:
　　
# 默认设置是  noeviction
　　
# maxmemory-policy noeviction
　　
可以根据情况自定义策略，比如
　　
maxmemory-policy volatile-lru
　　
# LRU and minimal TTL algorithms are not precise algorithms but approximated
　　
# algorithms (in order to save memory), so you can tune it for speed or
　　
# accuracy. For default Redis will check five keys and pick the one that was
　　
# used less recently, you can change the sample size using the following
　　
# configuration directive.
　　
#
　　
# The default of 5 produces good enough results. 10 Approximates very closely
　　
# true LRU but costs a bit more CPU. 3 is very fast but not very accurate.
　　
# 默认值为5产生足够好的结果。 10近似非常接近真实的LRU，但成本更多的CPU。 3是非常快，但不是很准确。
　　
# maxmemory-samples 5  #所以一般都是默认
　　
############################## APPEND ONLY 模式 ###############################
　　
# 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).
　　
#默认情况下，Redis异步地转储磁盘上的数据集。 这种模式在许多应用程序中是足够好的，
　　
但是Redis进程或断电的问题可能导致几分钟的写入丢失（取决于配置的保存点）。
　　
# 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.
　　
# 仅附加文件是可提供更好耐久性的替代持久性模式。 例如，使用默认数据fsync策略（见后面的配置文件）
　　
# Redis在一个戏剧性的事件，如服务器断电，丢失只有一秒的写入，或一个单一的写如果Redis进程本身发生错误，
　　
# 但是操作系统仍然正常运行。
　　
# 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.
　　
# AOF和RDB持久性可以同时启用而没有问题。 如果在启动时启用AOF，Redis将加载AOF，这是具有更好的持久性保证的文件。
　　
# Please check http://redis.io/topics/persistence for more information.
　　
appendonly no    ##aof日志的类型默认是no，如果要保持更好的数据持久性，设置为yes
　　
补充：appendonly yes/no  appendonly配置，指出是否在每次更新操作后进行日志记录，如果不开启，可能会在断电时导致一段时间内的数据丢失。
　　
# The name of the append only file (default: "appendonly.aof")
　　
仅追加文件的名称（默认值：“appendonly.aof”）
　　
appendfilename "appendonly.aof"
　　
# The fsync() call tells the Operating System to actually write data on disk
　　
# instead to wait for more data in the output buffer. Some OS will really flush
　　
# data on disk, some other OS will just try to do it ASAP.（as soon as possible）
　　
#
　　
# Redis supports three different modes:
　　
#
　　
# no: don't fsync, just let the OS flush the data when it wants. Faster.
　　
# always: fsync after every write to the append only log . Slow, Safest.
　　
# everysec: fsync only one time every second. Compromise.
　　
#
　　
# The default is "everysec", as that's usually the right compromise between
　　
# speed and data safety. It's up to you to understand if you can relax this to
　　
# "no" that will let the operating system flush the output buffer when
　　
# it wants, for better performances (but if you can live with the idea of
　　
# some data loss consider the default persistence mode that's snapshotting),
　　
# or on the contrary, use "always" that's very slow but a bit safer than
　　
# everysec.
　　
#
　　
# More details please check the following article:
　　
# http://antirez.com/post/redis-persistence-demystified.html
　　
#
　　
# If unsure, use "everysec".
　　
# appendfsync always
　　
appendfsync everysec    #默认everysec即可
　　
# appendfsync no
　　
注：appendfsync no/always/everysec ，appendfsync是Redis将OS数据缓冲区中数据刷新到磁盘的策略
　　
no表示操作系统进行数据缓存同步到磁盘，always表示每次更新操作后手动调用fsync()将数据写到磁盘，everysec表示每秒同步一次，默认是everysec。
　　
# 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.
　　
如果有延迟问题，请将其设置为“yes”。 否则，从耐久性的角度看，它是“no”，这是最安全的选择。
　　
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.
　　
  指定一个百分比为零，以禁用自动AOF重写功能。
　　
auto-aof-rewrite-percentage 100
　　
auto-aof-rewrite-min-size 64mb
　　

　　
# An AOF file may be found to be truncated at the end during the Redis
　　
# startup process, when the AOF data gets loaded back into memory.
　　
# This may happen when the system where Redis is running
　　
# crashes, especially when an ext4 filesystem is mounted without the
　　
# data=ordered option (however this can't happen when Redis itself
　　
# crashes or aborts but the operating system still works correctly).
　　
#
　　
# Redis can either exit with an error when this happens, or load as much
　　
# data as possible (the default now) and start if the AOF file is found
　　
# to be truncated at the end. The following option controls this behavior.
　　
#
　　
# If aof-load-truncated is set to yes, a truncated AOF file is loaded and
　　
# the Redis server starts emitting a log to inform the user of the event.
　　
# Otherwise if the option is set to no, the server aborts with an error
　　
# and refuses to start. When the option is set to no, the user requires
　　
# to fix the AOF file using the "redis-check-aof" utility before to restart
　　
# the server.
　　
#
　　
# Note that if the AOF file will be found to be corrupted in the middle
　　
# the server will still exit with an error. This option only applies when
　　
# Redis will try to read more data from the AOF file but not enough bytes
　　
# will be found.
　　
请注意，如果AOF文件将被发现在中间被损坏，服务器仍将退出并出现错误。此选项仅在Redis尝试从AOF文件读取更多数据但找不到足够的字节时适用。
　　
aof-load-truncated 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 exceed the maximum execution time only the
　　
# SCRIPT KILL and SHUTDOWN NOSAVE commands are available. The first can be
　　
# used to stop a script that did not yet called write commands. The second
　　
# is the only way to shut down the server in the case a write commands was
　　
# already issue by the script but the user don't want to wait for the natural
　　
# termination of the script.
　　
#
　　
# Set it to 0 or a negative value for unlimited execution without warnings.
　　
lua-time-limit 5000
　　
################################ REDIS 集群  ###############################
　　
#
　　
# 启用或停用集群
　　
# cluster-enabled yes
　　
# Every cluster node has a cluster configuration file. This file is not
　　
# intended to be edited by hand. It is created and updated by Redis nodes.
　　
# Every Redis Cluster node requires a different cluster configuration file.
　　
# Make sure that instances running in the same system does not have
　　
# overlapping cluster configuration file names.
　　
# 集群配置文件
　　
# 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.
　　
# 集群节点超时时间
　　
# cluster-node-timeout 15000
　　
# A slave of a failing master will avoid to start a failover if its data
　　
# looks too old.
　　
# There is no simple way for a slave to actually have a exact measure of
　　
# its "data age", so the following two checks are performed:
　　
#
　　
# 1) If there are multiple slaves able to failover, they exchange messages
　　
#    in order to try to give an advantage to the slave with the best
　　
#    replication offset (more data from the master processed).
　　
#    Slaves will try to get their rank by offset, and apply to the start
　　
#    of the failover a delay proportional to their rank.
　　
#
　　
# 2) Every single slave computes the time of the last interaction with
　　
#    its master. This can be the last ping or command received (if the master
　　
#    is still in the "connected" state), or the time that elapsed since the
　　
#    disconnection with the master (if the replication link is currently down).
　　
#    If the last interaction is too old, the slave will not try to failover
　　
#    at all.
　　
#
　　
# The point "2" can be tuned by user. Specifically a slave will not perform
　　
# the failover if, since the last interaction with the master, the time
　　
# elapsed is greater than:
　　
#
　　
#   (node-timeout * slave-validity-factor) + repl-ping-slave-period
　　
#
　　
# So for example if node-timeout is 30 seconds, and the slave-validity-factor
　　
# is 10, and assuming a default repl-ping-slave-period of 10 seconds, the
　　
# slave will not try to failover if it was not able to talk with the master
　　
# for longer than 310 seconds.
　　
#
　　
# A large slave-validity-factor may allow slaves with too old data to failover
　　
# a master, while a too small value may prevent the cluster from being able to
　　
# elect a slave at all.
　　
#
　　
# For maximum availability, it is possible to set the slave-validity-factor
　　
# to a value of 0, which means, that slaves will always try to failover the
　　
# master regardless of the last time they interacted with the master.
　　
# (However they'll always try to apply a delay proportional to their
　　
# offset rank).
　　
#
　　
# Zero is the only value able to guarantee that when all the partitions heal
　　
# the cluster will always be able to continue.
　　
#
　　
# cluster-slave-validity-factor 10
　　
# Cluster slaves are able to migrate to orphaned masters, that are masters
　　
# that are left without working slaves. This improves the cluster ability
　　
# to resist to failures as otherwise an orphaned master can't be failed over
　　
# in case of failure if it has no working slaves.
　　
#
　　
# Slaves migrate to orphaned masters only if there are still at least a
　　
# given number of other working slaves for their old master. This number
　　
# is the "migration barrier". A migration barrier of 1 means that a slave
　　
# will migrate only if there is at least 1 other working slave for its master
　　
# and so forth. It usually reflects the number of slaves you want for every
　　
# master in your cluster.
　　
#
　　
# Default is 1 (slaves migrate only if their masters remain with at least
　　
# one slave). To disable migration just set it to a very large value.
　　
# A value of 0 can be set but is useful only for debugging and dangerous
　　
# in production.
　　
#
　　
# cluster-migration-barrier 1
　　
# In order to setup your cluster make sure to read the documentation
　　
# available at http://redis.io web site.
　　
################################## SLOW LOG ###################################
　　
# The Redis Slow Log is a system to log queries that exceeded a specified
　　
# execution time. The execution time does not include the I/O operations
　　
# like talking with the client, sending the reply and so forth,
　　
# but just the time needed to actually execute the command (this is the only
　　
# stage of command execution where the thread is blocked and can not serve
　　
# other requests in the meantime).
　　
# You can configure the slow log with two parameters: one tells Redis
　　
# what is the execution time, in microseconds, to exceed in order for the
　　
# command to get logged, and the other parameter is the length of the
　　
# slow log. When a new command is logged the oldest one is removed from the
　　
# queue of logged commands.
　　
# The following time is expressed in microseconds, so 1000000 is equivalent
　　
# to one second. Note that a negative number disables the slow log, while
　　
# a value of zero forces the logging of every command.
　　
slowlog-log-slower-than 10000
　　
# There is no limit to this length. Just be aware that it will consume memory.
　　
# You can reclaim memory used by the slow log with SLOWLOG RESET.
　　
slowlog-max-len 128
　　
############################# Event notification ##############################
　　
# Redis can notify Pub/Sub clients about events happening in the key space.
　　
# This feature is documented at http://redis.io/topics/keyspace-events
　　
#
　　
# For instance if keyspace events notification is enabled, and a client
　　
# performs a DEL operation on key "foo" stored in the Database 0, two
　　
# messages will be published via Pub/Sub:
　　
#
　　
# PUBLISH __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
　　
#  by zero or multiple characters. The empty string means that notifications
　　
#  are disabled at all.
　　
#
　　
#  Example: to enable list and generic events, from the point of view of the
　　
#           event name, use:
　　
#
　　
#  notify-keyspace-events Elg
　　
#
　　
#  Example 2: to get the stream of the expired keys subscribing to channel
　　
#             name __keyevent@0__:expired use:
　　
#
　　
#  notify-keyspace-events Ex
　　
#
　　
#  By default all notifications are disabled because most users don't need
　　
#  this feature and the feature has some overhead. Note that if you don't
　　
#  specify at least one of K or E, no events will be delivered.
　　
notify-keyspace-events ""
　　
############################### ADVANCED CONFIG ###############################
　　
# Hashes are encoded using a memory efficient data structure when they have a
　　
# small number of entries, and the biggest entry does not exceed a given
　　
# threshold. These thresholds can be configured using the following directives.
　　
hash-max-ziplist-entries 512
　　
hash-max-ziplist-value 64
　　
# Similarly to hashes, small lists are also encoded in a special way in order
　　
# to save a lot of space. The special representation is only used when
　　
# you are under the following limits:
　　
list-max-ziplist-entries 512
　　
list-max-ziplist-value 64
　　
# Sets have a special encoding in just one case: when a set is composed
　　
# of just strings that happens to be integers in radix 10 in the range
　　
# of 64 bit signed integers.
　　
# The following configuration setting sets the limit in the size of the
　　
# set in order to use this special memory saving encoding.
　　
set-max-intset-entries 512
　　
# Similarly to hashes and lists, sorted sets are also specially encoded in
　　
# order to save a lot of space. This encoding is only used when the length and
　　
# elements of a sorted set are below the following limits:
　　
zset-max-ziplist-entries 128
　　
zset-max-ziplist-value 64
　　
# HyperLogLog sparse representation bytes limit. The limit includes the
　　
# 16 bytes header. When an HyperLogLog using the sparse representation crosses
　　
# this limit, it is converted into the dense representation.
　　
#
　　
# A value greater than 16000 is totally useless, since at that point the
　　
# dense representation is more memory efficient.
　　
#
　　
# The suggested value is ~ 3000 in order to have the benefits of
　　
# the space efficient encoding without slowing down too much PFADD,
　　
# which is O(N) with the sparse encoding. The value can be raised to
　　
# ~ 10000 when CPU is not a concern, but space is, and the data set is
　　
# composed of many HyperLogLogs with cardinality in the 0 - 15000 range.
　　
hll-sparse-max-bytes 3000
　　
# Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in
　　
# order to help rehashing the main Redis hash table (the one mapping top-level
　　
# keys to values). The hash table implementation Redis uses (see dict.c)
　　
# performs a lazy rehashing: the more operation you run into a hash table
　　
# that is rehashing, the more rehashing "steps" are performed, so if the
　　
# server is idle the rehashing is never complete and some more memory is used
　　
# by the hash table.
　　
#
　　
# The default is to use this millisecond 10 times every second in order to
　　
# active rehashing the main dictionaries, freeing memory when possible.
　　
#
　　
# If unsure:
　　
# use "activerehashing no" if you have hard latency requirements and it is
　　
# not a good thing in your environment that Redis can reply form time to time
　　
# to queries with 2 milliseconds delay.
　　
#
　　
# use "activerehashing yes" if you don't have such hard requirements but
　　
# want to free memory asap when possible.
　　
activerehashing yes
　　
# The client output buffer limits can be used to force disconnection of clients
　　
# that are not reading data from the server fast enough for some reason (a
　　
# common reason is that a Pub/Sub client can't consume messages as fast as the
　　
# publisher can produce them).
　　
# The limit can be set differently for the three different classes of clients:
　　
# normal -> normal clients
　　
# slave  -> slave clients and MONITOR clients
　　
# pubsub -> clients subscribed to at least one pubsub channel or pattern
　　
#
　　
# The syntax of every client-output-buffer-limit directive is the following:
　　
#
　　
# client-output-buffer-limit   
　　
#
　　
# A client is immediately disconnected once the hard limit is reached, or if
　　
# the soft limit is reached and remains reached for the specified number of
　　
# seconds (continuously).
　　
# So for instance if the hard limit is 32 megabytes and the soft limit is
　　
# 16 megabytes / 10 seconds, the client will get disconnected immediately
　　
# if the size of the output buffers reach 32 megabytes, but will also get
　　
# disconnected if the client reaches 16 megabytes and continuously overcomes
　　
# the limit for 10 seconds.
　　
#
　　
# By default normal clients are not limited because they don't receive data
　　
# without asking (in a push way), but just after a request, so only
　　
# asynchronous clients may create a scenario where data is requested faster
　　
# than it can read.
　　
#
　　
# Instead there is a default limit for pubsub and slave clients, since
　　
# subscribers and slaves receive data in a push fashion.
　　
#
　　
# Both the hard or the soft limit can be disabled by setting them to zero.
　　
client-output-buffer-limit normal 0 0 0
　　
client-output-buffer-limit slave 256mb 64mb 60
　　
client-output-buffer-limit pubsub 32mb 8mb 60
　　
# Redis calls an internal function to perform many background tasks, like
　　
# closing connections of clients in timeout, purging expired keys that are
　　
# never requested, and so forth.
　　
#
　　
# Not all tasks are performed with the same frequency, but Redis checks for
　　
# tasks to perform accordingly to the specified "hz" value.
　　
#
　　
# By default "hz" is set to 10. Raising the value will use more CPU when
　　
# Redis is idle, but at the same time will make Redis more responsive when
　　
# there are many keys expiring at the same time, and timeouts may be
　　
# handled with more precision.
　　
#
　　
# The range is between 1 and 500, however a value over 100 is usually not
　　
# a good idea. Most users should use the default of 10 and raise this up to
　　
# 100 only in environments where very low latency is required.
　　
hz 10
　　
# When a child rewrites the AOF file, if the following option is enabled
　　
# the file will be fsync-ed every 32 MB of data generated. This is useful
　　
# in order to commit the file to the disk more incrementally and avoid
　　
# big latency spikes.
　　
aof-rewrite-incremental-fsync yes