[转] redis.conf 配置文件解读

运维的坑 2016-01-13 12:09 暂无评论

渣英语,贴的是 oschina 的帖子,虽然相隔有一年了但基本上查到的资料翻译解释看的我难受,看来看去这份配置翻译应该最合适了。

# redis 配置文件示例
 
# 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 等酱紫:
#
# 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
 
################################## INCLUDES ###################################
 
# 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。
#
# 但是要注意哦,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(外国人真啰嗦)。
#
# 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。
# 当redis作为守护进程运行的时候,它会写一个 pid 到 /var/run/redis.pid 文件里面。
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己制定它的文件位置。
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。
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 ""
 
# 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 <dbid> 命令选择一个不同的数据库,
# 但是 dbid 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 <间隔时间(秒)> <写入次数>
#
#   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 秒后如果至少有 1 个 key 的值变化,则保存
#   300 秒后如果至少有 10 个 key 的值变化,则保存
#   60 秒后如果至少有 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。
#
# 然而你要是安装了靠谱的监控,你可能不希望 redis 这样做,那你就改成 no 好了。
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 的文件位置
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 ./
 
################################# 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。
# 注意这个只需要在 slave 上配置。
#
# slaveof <masterip> <masterport>
 
# 如果 master 需要密码认证,就在这里设置
# masterauth <master-password>
 
# 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) 如果为 no ,在你执行除了 info he salveof 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。
slave-read-only yes
 
# 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.
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
 
# 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.
#
# The N slaves need to be in "online" state.
#
# The lag in seconds, that must be <= the specified value, is calculated from
# the last ping received from the slave, that is usually sent every second.
#
# This option does not GUARANTEES that N replicas will accept the write, but
# will limit the window of exposure for lost writes in case not enough slaves
# are available, to the specified number of seconds.
#
# For example to require at least 3 slaves with a lag <= 10 seconds use:
#
# min-slaves-to-write 3
# min-slaves-max-lag 10
#
# Setting one or the other to 0 disables the feature.
#
# By default min-slaves-to-write is set to 0 (feature disabled) and
# min-slaves-max-lag is set to 10.
 
################################## 安全 ###################################
 
# Require clients to issue AUTH <PASSWORD> before processing any other
# commands.  This might be useful in environments in which you do not trust
# others with access to the host running redis-server.
#
# This should stay commented out for backward compatibility and because most
# people do not need auth (e.g. they run their own servers).
# 
# Warning: since Redis is pretty fast an outside user can try up to
# 150k passwords per second against a good box. This means that you should
# use a very strong password otherwise it will be very easy to break.
# 
# 设置认证密码
# 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 slaves may cause problems.
 
################################### 限制 ####################################
 
# 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).
#
# 一旦达到最大限制,redis 将关闭所有的新连接
# 并发送一个‘max number of clients reached’的错误。
#
# maxclients 10000
 
# 如果你设置了这个值,当缓存的数据容量达到这个值, redis 将根据你选择的
# eviction 策略来移除一些 keys。
#
# 如果 redis 不能根据策略移除 keys ,或者是策略被设置为 ‘noeviction’,
# redis 将开始响应错误给命令,如 set,lpush 等等,
# 并继续响应只读的命令,如 get
#
# This option is usually useful when using Redis as an LRU cache, or to set
# a hard memory limit for an instance (using the 'noeviction' policy).
#
# WARNING: If you have slaves attached to an instance with maxmemory on,
# the size of the output buffers needed to feed the slaves are subtracted
# from the used memory count, so that network problems / resyncs will
# not trigger a loop where keys are evicted, and in turn the output
# buffer of slaves is full with DELs of keys evicted triggering the deletion
# of more keys, and so forth until the database is completely emptied.
#
# In short... if you have slaves attached it is suggested that you set a lower
# limit for maxmemory so that there is some free RAM on the system for slave
# output buffers (but this is not needed if the policy is 'noeviction').
#
# 最大使用内存
# maxmemory <bytes>
 
# 最大内存策略,你有 5 个选择。
# 
# volatile-lru -> remove the key with an expire set using an LRU algorithm
# volatile-lru -> 使用 LRU 算法移除包含过期设置的 key 。
# allkeys-lru -> remove any key accordingly to the LRU algorithm
# allkeys-lru -> 根据 LRU 算法移除所有的 key 。
# volatile-random -> remove a random key with an expire set
# allkeys-random -> remove a random key, any key
# volatile-ttl -> remove the key with the nearest expire time (minor TTL)
# noeviction -> don't expire at all, just return an error on write operations
# noeviction -> 不让任何 key 过期,只是给写入操作返回一个错误
# 
# 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:
#
# maxmemory-policy noeviction
 
# LRU and minimal TTL algorithms are not precise algorithms but approximated
# algorithms (in order to save memory), so you can tune it for speed or
# accuracy. For default Redis will check five keys and pick the one that was
# used less recently, you can change the sample size using the following
# configuration directive.
#
# The default of 5 produces good enough results. 10 Approximates very closely
# true LRU but costs a bit more CPU. 3 is very fast but not very accurate.
#
# maxmemory-samples 5
 
############################## APPEND ONLY MODE ###############################
 
# By default Redis asynchronously dumps the dataset on disk. This mode is
# good enough in many applications, but an issue with the Redis process or
# a power outage may result into a few minutes of writes lost (depending on
# the configured save points).
#
# The Append Only File is an alternative persistence mode that provides
# much better durability. For instance using the default data fsync policy
# (see later in the config file) Redis can lose just one second of writes in a
# dramatic event like a server power outage, or a single write if something
# wrong with the Redis process itself happens, but the operating system is
# still running correctly.
#
# AOF and RDB persistence can be enabled at the same time without problems.
# If the AOF is enabled on startup Redis will load the AOF, that is the file
# with the better durability guarantees.
#
# Please check http://redis.io/topics/persistence for more information.
 
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 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.
#
# Redis supports three different modes:
#
# no: don't fsync, just let the OS flush the data when it wants. Faster.
# always: fsync after every write to the append only log . Slow, Safest.
# everysec: fsync only one time every second. Compromise.
#
# The default is "everysec", as that's usually the right compromise between
# speed and data safety. It's up to you to understand if you can relax this to
# "no" that will let the operating system flush the output buffer when
# it wants, for better performances (but if you can live with the idea of
# some data loss consider the default persistence mode that's snapshotting),
# or on the contrary, use "always" that's very slow but a bit safer than
# everysec.
#
# More details please check the following article:
# http://antirez.com/post/redis-persistence-demystified.html
#
# If unsure, use "everysec".
 
# appendfsync always
appendfsync everysec
# appendfsync no
 
# When the AOF fsync policy is set to always or everysec, and a background
# saving process (a background save or AOF log background rewriting) is
# performing a lot of I/O against the disk, in some Linux configurations
# Redis may block too long on the fsync() call. Note that there is no fix for
# this currently, as even performing fsync in a different thread will block
# our synchronous write(2) call.
#
# In order to mitigate this problem it's possible to use the following option
# that will prevent fsync() from being called in the main process while a
# BGSAVE or BGREWRITEAOF is in progress.
#
# This means that while another child is saving, the durability of Redis is
# the same as "appendfsync none". In practical terms, this means that it is
# possible to lose up to 30 seconds of log in the worst scenario (with the
# default Linux settings).
# 
# If you have latency problems turn this to "yes". Otherwise leave it as
# "no" that is the safest pick from the point of view of durability.
 
no-appendfsync-on-rewrite no
 
# Automatic rewrite of the append only file.
# Redis is able to automatically rewrite the log file implicitly calling
# BGREWRITEAOF when the AOF log size grows by the specified percentage.
# 
# This is how it works: Redis remembers the size of the AOF file after the
# latest rewrite (if no rewrite has happened since the restart, the size of
# the AOF at startup is used).
#
# This base size is compared to the current size. If the current size is
# bigger than the specified percentage, the rewrite is triggered. Also
# you need to specify a minimal size for the AOF file to be rewritten, this
# is useful to avoid rewriting the AOF file even if the percentage increase
# is reached but it is still pretty small.
#
# Specify a percentage of zero in order to disable the automatic AOF
# rewrite feature.
 
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
 
################################ 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.
#
# 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 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@<db>__ prefix.
#  E     Keyevent events, published with __keyevent@<db>__ prefix.
#  g     Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ...
#  $     String commands
#  l     List commands
#  s     Set commands
#  h     Hash commands
#  z     Sorted set commands
#  x     Expired events (events generated every time a key expires)
#  e     Evicted events (events generated when a key is evicted for maxmemory)
#  A     Alias for g$lshzxe, so that the "AKE" string means all the events.
#
#  The "notify-keyspace-events" takes as argument a string that is composed
#  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 <class> <hard limit> <soft limit> <soft seconds>
#
# A client is immediately disconnected once the hard limit is reached, or if
# the soft limit is reached and remains reached for the specified number of
# seconds (continuously).
# So for instance if the hard limit is 32 megabytes and the soft limit is
# 16 megabytes / 10 seconds, the client will get disconnected immediately
# if the size of the output buffers reach 32 megabytes, but will also get
# disconnected if the client reaches 16 megabytes and continuously overcomes
# the limit for 10 seconds.
#
# By default normal clients are not limited because they don't receive data
# without asking (in a push way), but just after a request, so only
# asynchronous clients may create a scenario where data is requested faster
# than it can read.
#
# Instead there is a default limit for pubsub and 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

再贴一份 redis2.8 的配置说明

#daemonize no  默认情况下, redis 不是在后台运行的,如果需要在后台运行,把该项的值更改为 yes
daemonize yes
#  当 redis 在后台运行的时候, Redis 默认会把 pid 文件放在 /var/run/redis.pid ,你可以配置到其他地址。
#  当运行多个 redis 服务时,需要指定不同的 pid 文件和端口
pidfile /var/run/redis_6379.pid
#  指定 redis 运行的端口,默认是 6379
port 6379
#  在高并发的环境中,为避免慢客户端的连接问题,需要设置一个高速后台日志
tcp-backlog 511
#  指定 redis 只接收来自于该 IP 地址的请求,如果不进行设置,那么将处理所有请求
# bind 192.168.1.100 10.0.0.1
# bind 127.0.0.1
#  设置客户端连接时的超时时间,单位为秒。当客户端在这段时间内没有发出任何指令,那么关闭该连接
# 0 是关闭此设置
timeout 0
# TCP keepalive
#  在 Linux 上,指定值(秒)用于发送 ACKs 的时间。注意关闭连接需要双倍的时间。默认为 0 。
tcp-keepalive 0
#  指定日志记录级别,生产环境推荐 notice
# Redis 总共支持四个级别: debug 、 verbose 、 notice 、 warning ,默认为 verbose
# debug     记录很多信息,用于开发和测试
# varbose   有用的信息,不像 debug 会记录那么多
# notice    普通的 verbose ,常用于生产环境
# warning   只有非常重要或者严重的信息会记录到日志
loglevel notice
#  配置 log 文件地址
#  默认值为 stdout ,标准输出,若后台模式会输出到 /dev/null 。
logfile /var/log/redis/redis.log
#  可用数据库数
#  默认值为 16 ,默认数据库为 0 ,数据库范围在 0- ( database-1 )之间
databases 16
################################ 快照#################################
#  保存数据到磁盘,格式如下 :
#   save <seconds> <changes>
#    指出在多长时间内,有多少次更新操作,就将数据同步到数据文件 rdb 。
#    相当于条件触发抓取快照,这个可以多个条件配合
#    比如默认配置文件中的设置,就设置了三个条件
#   save 900 1  900 秒内至少有 1 个 key 被改变
#   save 300 10  300 秒内至少有 300 个 key 被改变
#   save 60 10000  60 秒内至少有 10000 个 key 被改变
# save 900 1
# save 300 10
# save 60 10000
#  后台存储错误停止写。
stop-writes-on-bgsave-error yes
#  存储至本地数据库时(持久化到 rdb 文件)是否压缩数据,默认为 yes
rdbcompression yes
# RDB 文件的是否直接偶像 chcksum
rdbchecksum yes
#  本地持久化数据库文件名,默认值为 dump.rdb
dbfilename dump.rdb
#  工作目录
#  数据库镜像备份的文件放置的路径。
#  这里的路径跟文件名要分开配置是因为 redis 在进行备份时,先会将当前数据库的状态写入到一个临时文件中,等备份完成,
#  再把该该临时文件替换为上面所指定的文件,而这里的临时文件和上面所配置的备份文件都会放在这个指定的路径当中。
# AOF 文件也会存放在这个目录下面
#  注意这里必须制定一个目录而不是文件
dir /var/lib/redis-server/
################################# 复制 #################################
#  主从复制 . 设置该数据库为其他数据库的从数据库 .
#  设置当本机为 slav 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 <masterip><masterport>
#  当 master 服务设置了密码保护时 ( 用 requirepass 制定的密码 )
# slave 服务连接 master 的密码
# masterauth <master-password>
#  当从库同主机失去连接或者复制正在进行,从机库有两种运行方式:
# 1)  如果 slave-serve-stale-data 设置为 yes( 默认设置 ) ,从库会继续响应客户端的请求
# 2)  如果 slave-serve-stale-data 是指为 no ,出去 INFO 和 SLAVOF 命令之外的任何请求都会返回一个
#     错误 "SYNC with master in progress"
slave-serve-stale-data yes
#  配置 slave 实例是否接受写。写 slave 对存储短暂数据(在同 master 数据同步后可以很容易地被删除)是有用的,但未配置的情况下,客户端写可能会发送问题。
#  从 Redis2.6 后,默认 slave 为 read-only
slaveread-only yes
#  从库会按照一个时间间隔向主库发送 PINGs. 可以通过 repl-ping-slave-period 设置这个时间间隔,默认是 10 秒
# repl-ping-slave-period 10
# repl-timeout  设置主库批量数据传输时间或者 ping 回复时间间隔,默认值是 60 秒
#  一定要确保 repl-timeout 大于 repl-ping-slave-period
# repl-timeout 60
#  在 slave socket 的 SYNC 后禁用 TCP_NODELAY
#  如果选择“ yes ” ,Redis 将使用一个较小的数字 TCP 数据包和更少的带宽将数据发送到 slave , 但是这可能导致数据发送到 slave 端会有延迟 , 如果是 Linux kernel 的默认配置,会达到 40 毫秒 .
#  如果选择 "no" ,则发送数据到 slave 端的延迟会降低,但将使用更多的带宽用于复制 .
repl-disable-tcp-nodelay no
#  设置复制的后台日志大小。
#  复制的后台日志越大, slave 断开连接及后来可能执行部分复制花的时间就越长。
#  后台日志在至少有一个 slave 连接时,仅仅分配一次。
# repl-backlog-size 1mb
#  在 master 不再连接 slave 后,后台日志将被释放。下面的配置定义从最后一个 slave 断开连接后需要释放的时间(秒)。
# 0 意味着从不释放后台日志
# repl-backlog-ttl 3600
#  如果 master 不能再正常工作,那么会在多个 slave 中,选择优先值最小的一个 slave 提升为 master ,优先值为 0 表示不能提升为 master 。
slave-priority 100
#  如果少于 N 个 slave 连接,且延迟时间 <=M 秒,则 master 可配置停止接受写操作。
#  例如需要至少 3 个 slave 连接,且延迟 <=10 秒的配置:
# min-slaves-to-write 3
# min-slaves-max-lag 10
#  设置 0 为禁用
#   默认 min-slaves-to-write 为 0 (禁用), min-slaves-max-lag 为 10
################################## 安全 ###################################
#  设置客户端连接后进行任何其他指定前需要使用的密码。
#  警告:因为 redis 速度相当快,所以在一台比较好的服务器下,一个外部的用户可以在一秒钟进行 150K 次的密码尝试,这意味着你需要指定非常非常强大的密码来防止暴力破解
# requirepass foobared
#  命令重命名 .
#  在一个共享环境下可以重命名相对危险的命令。比如把 CONFIG 重名为一个不容易猜测的字符。
#  举例 :
# rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
#  如果想删除一个命令,直接把它重命名为一个空字符 "" 即可,如下:
# rename-command CONFIG ""
################################### 约束###################################
#设置同一时间最大客户端连接数,默认无限制, 
#Redis 可以同时打开的客户端连接数为 Redis 进程可以打开的最大文件描述符数,
#如果设置  maxclients 0 ,表示不作限制。
#当客户端连接数到达限制时, Redis 会关闭新的连接并向客户端返回 max number of clients reached 错误信息
# maxclients 10000
#  指定 Redis 最大内存限制, Redis 在启动时会把数据加载到内存中,达到最大内存后, Redis 会按照清除策略尝试清除已到期的 Key
#  如果 Redis 依照策略清除后无法提供足够空间,或者策略设置为 ”noeviction” ,则使用更多空间的命令将会报错,例如 SET, LPUSH 等。但仍然可以进行读取操作
#  注意: Redis 新的 vm 机制,会把 Key 存放内存, Value 会存放在 swap 区
#  该选项对 LRU 策略很有用。
# maxmemory 的设置比较适合于把 redis 当作于类似 memcached 的缓存来使用,而不适合当做一个真实的 DB 。
#  当把 Redis 当做一个真实的数据库使用的时候,内存使用将是一个很大的开销
# maxmemory <bytes>
#  当内存达到最大值的时候 Redis 会选择删除哪些数据?有五种方式可供选择
# volatile-lru ->  利用 LRU 算法移除设置过过期时间的 key (LRU: 最近使用  Least RecentlyUsed )
# allkeys-lru ->  利用 LRU 算法移除任何 key
# volatile-random ->  移除设置过过期时间的随机 key
# allkeys->random -> remove a randomkey, any key
# volatile-ttl ->  移除即将过期的 key(minor TTL)
# noeviction ->  不移除任何可以,只是返回一个写错误
#  注意:对于上面的策略,如果没有合适的 key 可以移除,当写的时候 Redis 会返回一个错误
#  默认是 :  volatile-lru
# maxmemory-policy volatile-lru  
# LRU  和  minimal TTL 算法都不是精准的算法,但是相对精确的算法 ( 为了节省内存 ) ,随意你可以选择样本大小进行检测。
# Redis 默认的灰选择 3 个样本进行检测,你可以通过 maxmemory-samples 进行设置
# maxmemory-samples 3
############################## AOF###############################
#  默认情况下, redis 会在后台异步的把数据库镜像备份到磁盘,但是该备份是非常耗时的,而且备份也不能很频繁,如果发生诸如拉闸限电、拔插头等状况,那么将造成比较大范围的数据丢失。
#  所以 redis 提供了另外一种更加高效的数据库备份及灾难恢复方式。
#  开启 append only 模式之后, redis 会把所接收到的每一次写操作请求都追加到 appendonly.aof 文件中,当 redis 重新启动时,会从该文件恢复出之前的状态。
#  但是这样会造成 appendonly.aof 文件过大,所以 redis 还支持了 BGREWRITEAOF 指令,对 appendonly.aof 进行重新整理。
#  你可以同时开启 asynchronous dumps 和  AOF
appendonly no
# AOF 文件名称  ( 默认 : "appendonly.aof")
# appendfilename appendonly.aof
# Redis 支持三种同步 AOF 文件的策略 :
# no:  不进行同步,系统去操作  . Faster.
# always: always 表示每次有写操作都进行同步 . Slow, Safest.
# everysec:  表示对写操作进行累积,每秒同步一次 . Compromise.
#  默认是 "everysec" ,按照速度和安全折中这是最好的。
#  如果想让 Redis 能更高效的运行,你也可以设置为 "no" ,让操作系统决定什么时候去执行
#  或者相反想让数据更安全你也可以设置为 "always"
#  如果不确定就用  "everysec".
# appendfsync always
appendfsync everysec
# appendfsync no
# AOF 策略设置为 always 或者 everysec 时,后台处理进程 ( 后台保存或者 AOF 日志重写 ) 会执行大量的 I/O 操作
#  在某些 Linux 配置中会阻止过长的 fsync() 请求。注意现在没有任何修复,即使 fsync 在另外一个线程进行处理
#  为了减缓这个问题,可以设置下面这个参数 no-appendfsync-on-rewrite
no-appendfsync-on-rewrite no
# AOF  自动重写
#  当 AOF 文件增长到一定大小的时候 Redis 能够调用  BGREWRITEAOF  对日志文件进行重写
#  它是这样工作的: Redis 会记住上次进行些日志后文件的大小 ( 如果从开机以来还没进行过重写,那日子大小在开机的时候确定 )
#  基础大小会同现在的大小进行比较。如果现在的大小比基础大小大制定的百分比,重写功能将启动
#  同时需要指定一个最小大小用于 AOF 重写,这个用于阻止即使文件很小但是增长幅度很大也去重写 AOF 文件的情况
#  设置  percentage 为 0 就关闭这个特性
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
################################ LUASCRIPTING #############################
# 一个 Lua 脚本最长的执行时间为 5000 毫秒( 5 秒),如果为 0 或负数表示无限执行时间。
lua-time-limit 5000
################################LOW LOG################################
# Redis Slow Log  记录超过特定执行时间的命令。执行时间不包括 I/O 计算比如连接客户端,返回结果等,只是命令执行时间
#  可以通过两个参数设置 slow log :一个是告诉 Redis 执行超过多少时间被记录的参数 slowlog-log-slower-than( 微妙 ) ,
#  另一个是 slow log 的长度。当一个新命令被记录的时候最早的命令将被从队列中移除
#  下面的时间以微妙为单位,因此 1000000 代表一秒。
#  注意指定一个负数将关闭慢日志,而设置为 0 将强制每个命令都会记录
slowlog-log-slower-than 10000
#  对日志长度没有限制,只是要注意它会消耗内存
#  可以通过  SLOWLOG RESET 回收被慢日志消耗的内存
#  推荐使用默认值 128 ,当慢日志超过 128 时,最先进入队列的记录会被踢出
slowlog-max-len 128
################################  事件通知  #############################
#  当事件发生时, Redis 可以通知 Pub/Sub 客户端。
#  可以在下表中选择 Redis 要通知的事件类型。事件类型由单个字符来标识:
# K     Keyspace 事件,以 _keyspace@<db>_ 的前缀方式发布
# E     Keyevent 事件,以 _keysevent@<db>_ 的前缀方式发布
# g     通用事件(不指定类型),像 DEL, EXPIRE, RENAME, …
# $     String 命令
# s     Set 命令
# h     Hash 命令
# z     有序集合命令
# x     过期事件(每次 key 过期时生成)
# e     清除事件(当 key 在内存被清除时生成)
# A     g$lshzxe 的别称,因此 ”AKE” 意味着所有的事件
# notify-keyspace-events 带一个由 0 到多个字符组成的字符串参数。空字符串意思是通知被禁用。
#  例子:启用 list 和通用事件:
# notify-keyspace-events Elg
#  默认所用的通知被禁用,因为用户通常不需要改特性,并且该特性会有性能损耗。
#  注意如果你不指定至少 K 或 E 之一,不会发送任何事件。
notify-keyspace-events “”
##############################  高级配置  ###############################
#  当 hash 中包含超过指定元素个数并且最大的元素没有超过临界时,
# hash 将以一种特殊的编码方式(大大减少内存使用)来存储,这里可以设置这两个临界值
# Redis Hash 对应 Value 内部实际就是一个 HashMap ,实际这里会有 2 种不同实现,
#  这个 Hash 的成员比较少时 Redis 为了节省内存会采用类似一维数组的方式来紧凑存储,而不会采用真正的 HashMap 结构,对应的 valueredisObject 的 encoding 为 zipmap,
#  当成员数量增大时会自动转成真正的 HashMap, 此时 encoding 为 ht 。
hash-max-zipmap-entries 512
hash-max-zipmap-value 64  
#  和 Hash 一样,多个小的 list 以特定的方式编码来节省空间。
# list 数据类型节点值大小小于多少字节会采用紧凑存储格式。
list-max-ziplist-entries 512
list-max-ziplist-value 64
# set 数据类型内部数据如果全部是数值型,且包含多少节点以下会采用紧凑格式存储。
set-max-intset-entries 512
#  和 hashe 和 list 一样 , 排序的 set 在指定的长度内以指定编码方式存储以节省空间
# zsort 数据类型节点值大小小于多少字节会采用紧凑存储格式。
zset-max-ziplist-entries 128
zset-max-ziplist-value 64
# Redis 将在每 100 毫秒时使用 1 毫秒的 CPU 时间来对 redis 的 hash 表进行重新 hash ,可以降低内存的使用
#  当你的使用场景中,有非常严格的实时性需要,不能够接受 Redis 时不时的对请求有 2 毫秒的延迟的话,把这项配置为 no 。
#  如果没有这么严格的实时性要求,可以设置为 yes ,以便能够尽可能快的释放内存
activerehashing yes
# 客户端的输出缓冲区的限制,因为某种原因客户端从服务器读取数据的速度不够快,
# 可用于强制断开连接(一个常见的原因是一个发布 / 订阅客户端消费消息的速度无法赶上生产它们的速度)。
#  可以三种不同客户端的方式进行设置:
# normal ->  正常客户端
# slave  -> slave 和 MONITOR 客户端
# pubsub ->  至少订阅了一个 pubsub channel 或 pattern 的客户端
#  每个 client-output-buffer-limit 语法 :
# client-output-buffer-limit <class><hard limit> <soft limit> <soft seconds>
#  一旦达到硬限制客户端会立即断开,或者达到软限制并保持达成的指定秒数(连续)。
#  例如,如果硬限制为 32 兆字节和软限制为 16 兆字节 /10 秒,客户端将会立即断开
#  如果输出缓冲区的大小达到 32 兆字节,客户端达到 16 兆字节和连续超过了限制 10 秒,也将断开连接。
#  默认 normal 客户端不做限制,因为他们在一个请求后未要求时(以推的方式)不接收数据,
#  只有异步客户端可能会出现请求数据的速度比它可以读取的速度快的场景。
#  把硬限制和软限制都设置为 0 来禁用该特性
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit slave 256mb 64mb60
client-output-buffer-limit pubsub 32mb 8mb60
# Redis 调用内部函数来执行许多后台任务,如关闭客户端超时的连接,清除过期的 Key ,等等。
#  不是所有的任务都以相同的频率执行,但 Redis 依照指定的“ Hz ”值来执行检查任务。
#  默认情况下,“ Hz ”的被设定为 10 。
#  提高该值将在 Redis 空闲时使用更多的 CPU 时,但同时当有多个 key 同时到期会使 Redis 的反应更灵敏,以及超时可以更精确地处理。
#  范围是 1 到 500 之间,但是值超过 100 通常不是一个好主意。
#  大多数用户应该使用 10 这个预设值,只有在非常低的延迟的情况下有必要提高最大到 100 。
hz 10  
#  当一个子节点重写 AOF 文件时,如果启用下面的选项,则文件每生成 32M 数据进行同步。
aof-rewrite-incremental-fsync yes
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