一、redis安装
1、在centos下面安装gcc，我们使用yum(包管理器)安装，因为gcc依赖了很多东西，而有些包系统可能已经安装了，有些没有，所以下面的命令最后都执行一遍，在Xshell中执行下面的命令：
1）、 yum install cpp
2）、 yum install binutils
3 ）、yum install glibc-kernheaders
4 ）、yum install glibc-common
5 ）、yum install glibc-devel
6 ）、yum install gcc
7 ）、yum install make
备注：以上所有的包信息在安装完成的时候都会提示Complete，如果没有是Complete，而是Nothingtodo，则说明服务器已经安装了这个包，不需要再次安装，所以没关系，继续执行下一个命令即可。
2、进入下载压缩包的目录下
tar zxvf redis-3.2.9.tar.gz解压压缩包
压缩包已经解压到当前文件夹中
3、使用make命令编译
4、make install 安装
5、执行redis-server –v (查看版本命令)
1、在/var目录下创建redis文件夹
在/var/redis/中创建data、log、run文件夹
dump file、进程pid、log目录等，一般放在/var/redis/目录下
首先拷贝解压包下的redis.conf文件至/etc/redis
打开redis.conf文件
端口号（默认）
修改pid目录为新建目录
修改dump目录为新建目录
修改log存储目录为新建目录
把daemonize no（前端运行）改为daemonize yes（后台运行）
测试
三．服务及开机自启动
1、创建redis启动脚本
拷贝解压包下utils下redis启动脚本至/etc/init.d/
cp redis_init_script /etc/init.d/
修改脚本pid及conf路径为实际路径
2、给启动脚本添加权限
chmod +x /etc/init.d/redis_init_script
（相应的删除权限是 chmod –x /etc/init.d/redis_init_script）
可以在其他目录下通过service redis_init_script start/stop 命令启动和关闭redis
3、设置自启动
在启动脚本里加入redis启动优先级信息，如下
执行chkconfig redis on，成功
4、设置系统的overcommit_memory，执行
vi/etc/sysctl.conf
vm.overcommit_memory=1
执行：sysctlvm.overcommit_memory=1
内核参数overcommit_memory
它是内存分配策略
可选值：0、1、2。
0， 表示内核将检查是否有足够的可用内存供应用进程使用；如果有足够的可用内存，内存申请允许；否则，内存申请失败，并把错误返回给应用进程。
1， 表示内核允许分配所有的物理内存，而不管当前的内存状态如何。
2， 表示内核允许分配超过所有物理内存和交换空间总和的内存
附：redis.conf配置文件详解
# 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.
#Redis默认不是以守护进程的方式运行，可以通过该配置项修改，使用yes启用守护进程
daemonize no
# When running daemonized,Redis writes a pid file in /var/run/redis.pid by
# default. You can specify a custom pid file location here.
#当 Redis 以守护进程的方式运行的时候,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.pid
# Accept connections on the specified port,default is 6379.
# If port 0 is specified Redis will not listen on a TCP socket.
#端口没什么好说的
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.
#指定Redis可接收请求的IP地址,不设置将处理所有请求,建议生产环境中设置
# bind 127.0.0.1
# Close the connection after a client is idle for N seconds (0 to disable)
#客户端连接的超时时间,单位为秒,超时后会关闭连接
timeout 0
# Specify the log file name. Also 'stdout' 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/null
#配置 log 文件地址,默认打印在命令行终端的窗口上
logfile stdout
# Set the number of databases. The default database is DB 0,you can select
# a different one on a per-connection basis using SELECT <dbid> where
# dbid is a number between 0 and 'databases'-1
databases 16
#
# Save the DB on disk:
#
# save <seconds> <changes>
#
# 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.
#设置 Redis 进行数据库镜像的频率。
#900秒之内有1个keys发生变化时
#30秒之内有10个keys发生变化时
#60秒之内有10000个keys发生变化时
save 900 1
save 300 10
save 60 10000
# Compress string objects using LZF when dump .rdb databases?
# For default that's set to 'yes' as it's almost always a win.
# If you want to save some cpu in the saving child set it to 'no' but
# the dataset will likely be bigger if you have compressible values or keys.
#在进行镜像备份时,是否进行压缩
rdbcompression yes
# The filename where to dump the DB
dbfilename dump.rdb
# The working directory.
#
# The DB will be written inside this directory,with the filename specified
# above using the 'dbfilename' configuration directive.
#
# Also the Append Only File will be created inside this directory.
#
# Note that you must specify a directory here,not a file name.
dir ./
# Master-Slave replication. Use slaveof to make a Redis instance a copy of
# another Redis server. Note that the configuration is local to the slave
# so for example it is possible to configure the slave to save the DB with a
# different interval,or to listen to another port,and so on.
# slaveof <masterip> <masterport>
# If the master is password protected (using the "requirepass" configuration
# directive below) it is possible to tell the slave to authenticate before
# starting the replication synchronization process,otherwise the master will
# refuse the slave request.
#指定与主数据库连接时需要的密码验证
# masterauth <master-password>
# 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.
#设置客户端连接后进行任何其他指定前需要使用的密码。
警告:redis速度相当快,一个外部的用户可以在一秒钟进行150K次的密码尝试,你需要指定非常非常强大的密码来防止暴力破解。
# requirepass foobared
# Set the max number of connected clients at the same time. By default there
# is no limit,and it's up to the number of file descriptors the Redis process
# is able to open. The special value '0' means no limits.
# Once the limit is reached Redis will close all the new connections sending
# an error 'max number of clients reached'.
#限制同时连接的客户数量。当连接数超过这个值时,redis 将不再接收其他连接请求,客户端尝试连接时将收到 error 信息
# maxclients 128
# Don't use more memory than the specified amount of bytes.
# When the memory limit is reached Redis will try to remove keys
# accordingly to the eviction policy selected (see maxmemmory-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 cache,or to set
# an 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').
#设置redis能够使用的最大内存。当内存满了的时候,如果还接收到set命令,redis将先尝试剔除设置过expire信息的key,而不管该key的过期时间还没有到达。
#这样,redis将不再接收写请求,只接收get请求。maxmemory的设置比较适合于把redis当作于类似memcached 的缓存来使用
# maxmemory <bytes>
# By default Redis asynchronously dumps the dataset on disk. If you can live
# with the idea that the latest records will be lost if something like a crash
# happens this is the preferred way to run Redis. If instead you care a lot
# about your data and don't want to that a single record can get lost you should
# enable the append only mode: when this mode is enabled Redis will append
# every write operation received in the file appendonly.aof. This file will
# be read on startup in order to rebuild the full dataset in memory.
#
# Note that you can have both the async dumps and the append only file if you
# like (you have to comment the "save" statements above to disable the dumps).
# Still if append only mode is enabled Redis will load the data from the
# log file at startup ignoring the dump.rdb file.
#
# IMPORTANT: Check the BGREWRITEAOF to check how to rewrite the append
# log file in background when it gets too big.
#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。
appendonly no
# 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 if one second passed since the last fsync. Compromise.
#
# 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.
#
# If unsure,use "everysec".
#设置对 appendonly.aof 文件进行同步的频率。always 表示每次有写操作都进行同步,everysec 表示对写操作进行累积,每秒同步一次。
# appendfsync always
appendfsync everysec
# appendfsync no
# 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.
#但是需要注意的是,redis中,所有的key都会放在内存中,在内存不够时,只会把value 值放入交换区。
#这样保证了虽然使用虚拟内存,但性能基本不受影响,同时,你需要注意的是你要把vm-max-memory设置到足够来放下你的所有的key
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.
#设置虚拟内存的交换文件路径
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.
#在生产环境下,需要根据实际情况设置该值,最好不要使用默认的 0
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.
#总的虚拟内存大小 = vm-page-size * vm-pages
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.
#设置 VM IO 同时使用的线程数量。
vm-max-threads 4
# 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.
#redis 2.0 中引入了 hash 数据结构。
#hash 中包含超过指定元素个数并且最大的元素当没有超过临界时,hash 将以zipmap(又称为 small hash大大减少内存使用)来存储,这里可以设置这两个临界值
hash-max-zipmap-entries 512
hash-max-zipmap-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.
#开启之后,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
