redis的配置
# Redis configuration file example
# 内存单位
# Note on units: when memory size is needed, it is possible to specifiy
# 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.
# 后台运行，默认no
daemonize no
# 后台运行时，pid的存放位置
pidfile /var/run/redis.pid
# 端口为6379
port 6379
# If you want you can bind a single interface, if the bind option is not
# specified all the interfaces will listen for incoming connections.
#
# 如果你想绑定单一的接口，如果绑定选项不是定义的所有的监听接口。
# bind 127.0.0.1
# 定义用于监听请求连接的unix sock文件。这不是默认的，所以Redis不会监听一个没有
# 定义的unix socket。
# unixsocket /tmp/redis.sock
# unixsocketperm 755
# Close the connection after a client is idle for N seconds (0 to disable)
# 当客服端连接空闲，多少秒端口（0s 不断开）
timeout 0
########################### 日志 ####################################
# 设置日志级别
# debug(用于开发、测试)
# verbose(很多有用的信息，但是比debug少很多)
# notice(生产环境的使用)
# warning（很重要的日志信息）
loglevel verbose
# 日志文件默认为console输出。如果是后台运行，则什么都不输出
logfile stdout
# 确实使用系统的日志系统。默认为no
# syslog-enabled no
# 给系统日志设置身份
# syslog-ident redis
# 定义系统设备，默认为LOCAL0
# syslog-facility local0
# 设置database的数量,默认是DB 0,你可以选择不同的数据库连接
databases 16
################################ SNAPSHOTTING（快照） #################################
#
# Save the DB on disk:
#
# save <时间> <改变次数>
#
# 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 at all commenting all the "save" lines.
# 保存到磁盘的时候设置（将在时间或者修改次数达到后保存到磁盘）
# save 时间 改变次数
save 900 1 （900s《15分钟》、如果值修改1个key）
save 300 10 （300s《15分钟》、如果值修改10个key）
save 60 10000 （60s《1分钟》、如果值修改10000个key）
# 在备份的时候使用LZF方式压缩string对象？
# 默认是yes,大部分情况适用
rdbcompression yes
# The filename where to dump the DB
# 备份的数库的文件
dbfilename dump.rdb
# 工作目录，DB将被写在这个目录。默认目录，所有的数据都是以次为相对地址
dir ./
################################# REPLICATION（主从） #################################
# 主从复制,使用slaveof去从起来的Redis服务器复制Redis实例。这个配置对从库起作用。
# 例如，它可以配置从库定时去复制、监听、等操作
# slaveof <masterip> <masterport>
# 从库连接主库的密码
# masterauth <master-password>
# 如果从库丢失了连接，或者复制功能还在启动，有下面两种处理方式
# 1、如果该参数为yes（默认）,从库还是响应客服端的请求，可能需要输出数据，或者数据
设置为null
# 2、如果为no，则给客服端一个 SYNC with master in progress 的信息
slave-serve-stale-data yes
# 定时发送PINGS给master
# repl-ping-slave-period 10
# 主从的连接超时（很重要）
# repl-timeout 60
################################## SECURITY（安全） ###################################
# 需要client登录，通常使用在不同的主机上
# 一般都是跑在同一主机上，不需要使用账户密码
# 需要很难破解的密码
requirepass root
# Command renaming.
#
# It is possilbe to change the name of dangerous commands in a shared
# environment. For instance the CONFIG command may be renamed into something
# of hard to guess so that it will be still available for internal-use
# tools but not available for general clients.
#
# Example:
#
# rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
#
# It is also possilbe to completely kill a command renaming it into
# an empty string:
#
# rename-command CONFIG ""
################################### LIMITS（限制） ####################################
# 客服端连接数
# maxclients 128
# 使用打得bytes比大内存靠谱。当内存到上限，Redis会尝试删除定时的set。它就会
# 优先删除快要到时的keys和长时间保留的keys。Redis也会释放的lists中删除数据
# 如果都失败了，Redis将使用错误命来返回用户的写指令，只有读指令能正确使用
# 提醒：如果你把Redis当作一个cache，则设置maxmemory是一个好的习惯。当作一个
# 数据库，内存占用每周都会增加。很明显，当你长时间的使用后，Redis将会使用很多
# 的内存，你需要花时间提升。当最大的内存使用完之后，你会获取一个错误的写操作。
# maxmemory <bytes>
# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
# is reached? You can select among five behavior:
# 内存策略
# volatile-lru -> remove the key with an expire set using an LRU algorithm
# 使用LRU的算法来设置删除过期键
# allkeys-lru -> remove any key accordingly to the LRU algorithm
# 所有的key都根据LRU算法来删除
# volatile-random -> remove a random key with an expire set
# 随机删除过时的key
# allkeys->random -> remove a random key, any key
# 随机删除任意key
# volatile-ttl -> remove the key with the nearest expire time (minor TTL)
# 删除最近的过时key
# noeviction -> don't expire at all, just return an error on write operations
# 不删除过时key，只返回写错误提示
# Note: with all the kind of 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 volatile-lru
# LRU and minimal TTL algorithms are not precise algorithms but approximated
# algorithms (in order to save memory), so you can select as well the sample
# size to check. For instance for default Redis will check three keys and
# pick the one that was used less recently, you can change the sample size
# using the following configuration directive.
# LRU 和 TTL 算法都不是精准的算法而是近似算法（为了保存数据到内存），所以你能选择
# 简单的数字选项。默认值为3，你能改变这个配置
# maxmemory-samples 3
############################## APPEND ONLY MODE（内存数据存放到磁盘） ###############################
# Redis默认使用异步份方法来备份数据。如果你能用的想法，新的记录将如果像发生车祸失去生活是运行Redis的
# 首选方式。如果你很在乎你的数据，不想，一个记录可以失去你应使附加模式：
# 在该模式下启用Redis会将每一个写操作的文件appendonly.aof收到。此文件将在启动时读取，
# 以便在内存中重建完整的数据集。
# 注意，你能同时异步备份和单个文件追加数据,如果只加模式启用Redis会加载数据从日志文件而且在启动时忽略了dump.rdb文件
# IMPORTANT: Check the BGREWRITEAOF to check how to rewrite the append
# log file in background when it gets too big.
appendonly no
# The name of the append only file (default: "appendonly.aof")
# 备份文件的名称
# 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.
# fsync()告诉操作系统立即写数据到磁盘而不是等待更多的数据在输出缓存中，一些操作系统将写在磁盘，
# 有些尝试等待在些
# 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 if one second passed since the last fsync. Compromise.
# 选择no：不使用fsync，使用OS自己的刷新方式（快）。
# always：fsync将所有的都记录下拉（慢，安全）
# everysec：fsync会在上次的fsync是执行（妥协）
# The default is "everysec" 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 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.
# 默认为everysec,这常常是在快速和安全之间妥协。
# 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.
# 当AOF fsync策略被设置为always和everysec,而且有一个后台进程来保存数据。在一些linux
# 的配置中Redis可能在fsync()阻塞。注意现在还没法修复，甚至将使得安全写入模块阻塞
# 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.
# 为了减轻这个问题，下面的选项方式防止fsync()在主要线程中作为一个BGSAVE或者BGREWRITEAOF
# This means that while another child is saving the durability of Redis is
# the same as "appendfsync none", that in pratical terms means that it is
# possible to lost 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.
# 有潜在问题使用yes。另外no的持久安全性好
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 will growth by the specified percentage.
# 自动添加到文件
# This is how it works: Redis remembers the size of the AOF file after the
# latest rewrite (or if no rewrite 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 precentage of zero in order to disable the automatic AOF
# rewrite feature.
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
################################## SLOW LOG（慢日志） ###################################
# 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).
# Redis的满是日是系统记录的查询日志。
# 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.
# 下面的数字单位是毫秒，如果是负数则禁用日志
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.
# 日志长度可以不设限。但是为了内存消耗，你重设slow log的内存消耗
slowlog-max-len 1024
################################ VIRTUAL MEMORY（虚拟内存） ###############################
### WARNING! Virtual Memory is deprecated in Redis 2.4
### The use of Virtual Memory is strongly discouraged.
### WARNING! Virtual Memory is deprecated in Redis 2.4
### The use of Virtual Memory is strongly discouraged.
# Virtual Memory allows Redis to work with datasets bigger than the actual
# amount of RAM needed to hold the whole dataset in memory.
# In order to do so very used keys are taken in memory while the other keys
# are swapped into a swap file, similarly to what operating systems do
# with memory pages.
#
# To enable VM just set 'vm-enabled' to yes, and set the following three
# VM parameters accordingly to your needs.
vm-enabled no
# vm-enabled yes
# This is the path of the Redis swap file. As you can guess, swap files
# can't be shared by different Redis instances, so make sure to use a swap
# file for every redis process you are running. Redis will complain if the
# swap file is already in use.
#
# The best kind of storage for the Redis swap file (that's accessed at random)
# is a Solid State Disk (SSD).
#
# *** WARNING *** if you are using a shared hosting the default of putting
# the swap file under /tmp is not secure. Create a dir with access granted
# only to Redis user and configure Redis to create the swap file there.
vm-swap-file /tmp/redis.swap
# vm-max-memory configures the VM to use at max the specified amount of
# RAM. Everything that deos not fit will be swapped on disk *if* possible, that
# is, if there is still enough contiguous space in the swap file.
#
# With vm-max-memory 0 the system will swap everything it can. Not a good
# default, just specify the max amount of RAM you can in bytes, but it's
# better to leave some margin. For instance specify an amount of RAM
# that's more or less between 60 and 80% of your free RAM.
vm-max-memory 0
# Redis swap files is split into pages. An object can be saved using multiple
# contiguous pages, but pages can't be shared between different objects.
# So if your page is too big, small objects swapped out on disk will waste
# a lot of space. If you page is too small, there is less space in the swap
# file (assuming you configured the same number of total swap file pages).
#
# If you use a lot of small objects, use a page size of 64 or 32 bytes.
# If you use a lot of big objects, use a bigger page size.
# If unsure, use the default :)
vm-page-size 32
# Number of total memory pages in the swap file.
# Given that the page table (a bitmap of free/used pages) is taken in memory,
# every 8 pages on disk will consume 1 byte of RAM.
#
# The total swap size is vm-page-size * vm-pages
#
# With the default of 32-bytes memory pages and 134217728 pages Redis will
# use a 4 GB swap file, that will use 16 MB of RAM for the page table.
#
# It's better to use the smallest acceptable value for your application,
# but the default is large in order to work in most conditions.
vm-pages 134217728
# Max number of VM I/O threads running at the same time.
# This threads are used to read/write data from/to swap file, since they
# also encode and decode objects from disk to memory or the reverse, a bigger
# number of threads can help with big objects even if they can't help with
# I/O itself as the physical device may not be able to couple with many
# reads/writes operations at the same time.
#
# The special value of 0 turn off threaded I/O and enables the blocking
# Virtual Memory implementation.
vm-max-threads 4
############################### ADVANCED CONFIG（高级配置） ###############################
# Hashes are encoded in a special way (much more memory efficient) when they
# have at max a given numer of elements, and the biggest element does not
# exceed a given threshold. You can configure this limits with the following
# configuration directives.
#
hash-max-zipmap-entries 512
hash-max-zipmap-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
# 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 an hash table
# that is rhashing, 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
################################## INCLUDES ###################################
# Include one or more other config files here. This is useful if you
# have a standard template that goes to all redis server but also need
# to customize a few per-server settings. Include files can include
# other files, so use this wisely.
# 包括其它的配置文件。这在整个redis服务器中的标准化模版化很有用，但是同时
# 每一个服务器自定义一些设置。将配置文件分部分设置，很明智
# include /path/to/local.conf
# include /path/to/other.conf
