Redis在百度百科里的解释：Redis是一个开源的使用ANSI  C语言编写、支持网络、可基于内存亦可持久化的日志型、Key-Value数据库，并提供多种语言的API，包括C#、Java、PHP等等，甚至连Javascript都做了很好的封装。

       可见Redis的数据是持久化的，可以分担一个项目中的部分业务，Redis的数据是存储在服务器内存当中的，这样可以极大的加快访问速度，因为内存的读取速度远远超过磁盘和数据库，这在很大程序的上解决了大并发的困惑；同时Redis和Memcached不同，会按照设定的规律定期将数据同步到磁盘数据库，这样在Redis服务器宕机时也能保证数据的完整性。

       大家都知道Redis在全球最大的用户是新浪微博，新浪有最大的Redis集群，新浪最开始使用Memcached与Mysql配合，后来新浪又增加了Redis，而不是弃用Memcached，新浪加入Redis集群的初衷：

      1、Memcached存在命中率问题，这样大量请求会发送到Mysql，对于新浪微博这么大的并发无疑是一个灾难，Redis不存在命中率问题

      2、Redis相对于Memcached支持更多的数据类型，如string(字符串)、list(链表)、set(集合)、zset(有序集合)和hash（哈希类型）。这些数据类型都支持push/pop、add/remove及取交集并集和差集及更丰富的操作，而且这些操作都是原子性的

     3、Redis主从集群配置技术容易实现，维护成本低，项目复杂度低

     4、Redis的持久化存储从某种程度上解决了Cache宕机带来的雪崩现象

       当然，新浪并没有弃用Memcached+Mysql，用户的全量信息是在此结构中的，使用Redis带来的问题是，数据是持久化的，这是相当占用内存的，成本不可小觑。

      Redis(2.8.19目前最新稳定版本)的安装：

      1.下载：

          http://pan.baidu.com/s/1jGvJxBo

       2.安装

        解压下载文件：

        [root@jhq0229 src]# tar xzvf redis-stable.tar.gz
      

        编译安装：

        [root@jhq0229 src]# cd redis-stable

        [root@jhq0229 redis-stable]# make 

        [root@jhq0229 redis-stable]# make  PREFIX=/usr/local install

       

        配置：

        [root@jhq0229 redis-stable]# mkdir /etc/redis

       

        [root@jhq0229 redis-stable]# cp redis.conf /etc/redis/

       

         创建Redis数据及日志存放目录：

         [root@jhq0229 redis-stable]# mkdir /data/redis

         Redis配置文件详解：

        

daemonize：如果需要在后台运行，把该项心为yes
pidfile：配置多个pid的地址，默认在/var/run/redis.pid
bind：绑定ip，设置后只接受来自该ip的请求
port：监听端口，默认为6379
timeout：设置客户端连接时的超时时间，单位为秒
loglevel：分为4级，debug、verbose、notice、warning
logfile：配置log文件地址
databases：设置数据库的个数，默认使用的数据库为0
save：设置redis进行数据库镜像的频率
rdbcompression：在进行镜像备份时，是否进行压缩
Dbfilename：镜像备份文件的文件名
Dir：数据库镜像备份的文件放置路径
Slaveof：设置数据库为其他数据库的从数据库
Masterauth：主数据库连接需要的密码验证
Requirepass：设置登录登录时需要使用的密码
Maxclients：限制同时连接的客户数量
Maxmemory：设置redis能够使用的最大内存
Appendonly：开启append only模式
Appendfsync：设置对appendonly.aof文件同步的频率
vm-enabled：是否开启虚拟内存支持
vm-swap-file：设置虚拟内存的交换文件路径
vm-max-memory：设置redis使用的最大物理内存大小
vm-page-size：设置虚拟内存的页大小
vm-pages：设置交换文件的总的page数量
vm-max-threads：设置VMIO同时使用的线程数量
Glueoutputbuf：把小的输出缓存存放在一起
hash-max-zipmap-entries：设置hash的临界值
Activerehashing：重新hash

        配置自己的Redis集群(若不配置集群可以只配置Master)：

       [root@jhq0229 redis-stable]# vim /etc/redis/redis.conf

        我的Redis主从配置：

        主：192.168.1.18              认证密码：01130229

        从：192.168.1.16

        主Redis(Master)配置：

       

# Redis configuration file example

# Note on units: when memory size is needed, it is possible to specify
# it in the usual form of 1k 5GB 4M and so forth:
#
# 1k => 1000 bytes
# 1kb => 1024 bytes
# 1m => 1000000 bytes
# 1mb => 1024*1024 bytes
# 1g => 1000000000 bytes
# 1gb => 1024*1024*1024 bytes
#
# units are case insensitive so 1GB 1Gb 1gB are all the same.

################################## INCLUDES ###################################

# Include one or more other config files here.  This is useful if you
# have a standard template that goes to all Redis servers but also need
# to customize a few per-server settings.  Include files can include
# other files, so use this wisely.
#
# Notice option "include" won't be rewritten by command "CONFIG REWRITE"
# from admin or Redis Sentinel. Since Redis always uses the last processed
# line as value of a configuration directive, you'd better put includes
# at the beginning of this file to avoid overwriting config change at runtime.
#
# If instead you are interested in using includes to override configuration
# options, it is better to use include as the last line.
#
# include /path/to/local.conf
# include /path/to/other.conf

################################ GENERAL  #####################################

# By default Redis does not run as a daemon. Use 'yes' if you need it.
# Note that Redis will write a pid file in /var/run/redis.pid when daemonized.
#是否以后台进程方式运行
daemonize yes

# When running daemonized, Redis writes a pid file in /var/run/redis.pid by
# default. You can specify a custom pid file location here.
#以后台进行运行，需指定pid
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.
port 6379

# TCP listen() backlog.
#
# In high requests-per-second environments you need an high backlog in order
# to avoid slow clients connections issues. Note that the Linux kernel
# will silently truncate it to the value of /proc/sys/net/core/somaxconn so
# make sure to raise both the value of somaxconn and tcp_max_syn_backlog
# in order to get the desired effect.
tcp-backlog 511

# By default Redis listens for connections from all the network interfaces
# available on the server. It is possible to listen to just one or multiple
# interfaces using the "bind" configuration directive, followed by one or
# more IP addresses.
#
# Examples:
#
# bind 192.168.1.100 10.0.0.1
bind 192.168.1.18

# Close the connection after a client is idle for N seconds (0 to disable)
#客户端闲置N秒后关闭连接
timeout 30

tcp-keepalive 0

# Specify the server verbosity level.
# This can be one of:
# debug (a lot of information, useful for development/testing)
# verbose (many rarely useful info, but not a mess like the debug level)
# notice (moderately verbose, what you want in production probably)
# warning (only very important / critical messages are logged)
#日志级别
loglevel notice

#记录日志的文件名称
logfile "redlog"

# To enable logging to the system logger, just set 'syslog-enabled' to yes,
# and optionally update the other syslog parameters to suit your needs.
# syslog-enabled no

# Specify the syslog identity.
# syslog-ident redis

# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
# syslog-facility local0

# Set the number of databases. The default database is DB 0, you can select
# a different one on a per-connection basis using SELECT <dbid> where
# dbid is a number between 0 and 'databases'-1
#可用数据库数量
databases 16

################################ SNAPSHOTTING  ################################
#
# 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 completely by commenting out all "save" lines.
#
#   It is also possible to remove all the previously configured save
#   points by adding a save directive with a single empty string argument
#   like in the following example:
#
#   save ""
#当有一条数据更新，900秒后同步数据到磁盘数据库
save 900 1
#当有10条数据更新，300秒后同步数据到磁盘数据库
save 300 10
save 60 10000


stop-writes-on-bgsave-error yes

# 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.
#当dump .rdb的时候是否压缩数据对象，默认值为yes
rdbcompression yes

rdbchecksum yes

# The filename where to dump the DB
# 磁盘数据库文件名称
dbfilename myredis.rdb

#本地数据库存放路径
dir /data/redis/

################################# REPLICATION #################################
#Redis主从复制配置

#若当前服务为slave，在此处设置主服务的ip及端口
# slaveof <masterip> <masterport>

#若当前服务为slave，设置主服务的认证密码
# masterauth <master-password>


slave-serve-stale-data yes

#若当前为slave服务，设置slave是否为只读服务
#slave-read-only yes

# Replication SYNC strategy: disk or socket.
#
# -------------------------------------------------------
# WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY
# -------------------------------------------------------
#
# New slaves and reconnecting slaves that are not able to continue the replication
# process just receiving differences, need to do what is called a "full
# synchronization". An RDB file is transmitted from the master to the slaves.
# The transmission can happen in two different ways:
#
# 1) Disk-backed: The Redis master creates a new process that writes the RDB
#                 file on disk. Later the file is transferred by the parent
#                 process to the slaves incrementally.
# 2) Diskless: The Redis master creates a new process that directly writes the
#              RDB file to slave sockets, without touching the disk at all.
#
# With disk-backed replication, while the RDB file is generated, more slaves
# can be queued and served with the RDB file as soon as the current child producing
# the RDB file finishes its work. With diskless replication instead once
# the transfer starts, new slaves arriving will be queued and a new transfer
# will start when the current one terminates.
#
# When diskless replication is used, the master waits a configurable amount of
# time (in seconds) before starting the transfer in the hope that multiple slaves
# will arrive and the transfer can be parallelized.
#
# With slow disks and fast (large bandwidth) networks, diskless replication
# works better.
repl-diskless-sync no

repl-diskless-sync-delay 5

# Slaves send PINGs to server in a predefined interval. It's possible to change
# this interval with the repl_ping_slave_period option. The default value is 10
# seconds.
#
# repl-ping-slave-period 10


# repl-timeout 60

repl-disable-tcp-nodelay no

slave-priority 100

################################## SECURITY ###################################

# 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.
#认证密码
requirepass 01130229


################################### LIMITS ####################################

# Set the max number of connected clients at the same time. By default
# this limit is set to 10000 clients, however if the Redis server is not
# able to configure the process file limit to allow for the specified limit
# the max number of allowed clients is set to the current file limit
# minus 32 (as Redis reserves a few file descriptors for internal uses).
#
# Once the limit is reached Redis will close all the new connections sending
# an error 'max number of clients reached'.

# Don't use more memory than the specified amount of bytes.
# When the memory limit is reached Redis will try to remove keys
# according to the eviction policy selected (see maxmemory-policy).
#
# If Redis can't remove keys according to the policy, or if the policy is
# set to 'noeviction', Redis will start to reply with errors to commands
# that would use more memory, like SET, LPUSH, and so on, and will continue
# to reply to read-only commands like GET.
#
# This option is usually useful when using Redis as an LRU 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').
# maxmemory <bytes>

# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
# is reached. You can select among five behaviors:
#
# volatile-lru -> remove the key with an expire set using an LRU algorithm
# allkeys-lru -> remove any key according to the LRU algorithm
# 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
#
# Note: with any of the above policies, Redis will return an error on write
#       operations, when there are no suitable keys for eviction.
#
#       At the date of writing these commands are: set setnx setex append
#       incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd
#       sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby
#       zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby
#       getset mset msetnx exec sort
#
# The default is:
#
# maxmemory-policy 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
#
# maxmemory-samples 3

############################## 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).
#
appendonly no

# The name of the append only file (default: "appendonly.aof")#更新日志文件名称

#
#
# If unsure, use "everysec".
# appendfsync always
appendfsync everysec
# appendfsync no

no-appendfsync-on-rewrite no

auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb

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.
#
lua-time-limit 5000

################################## 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).
slowlog-log-slower-than 10000

slowlog-max-len 128

################################ LATENCY MONITOR ##############################

# The Redis latency monitoring subsystem samples different operations
# at runtime in order to collect data related to possible sources of
# latency of a Redis instance.
#

latency-monitor-threshold 0

############################# Event notification ##############################


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

list-max-ziplist-entries 512
list-max-ziplist-value 64

set-max-intset-entries 512

zset-max-ziplist-entries 128
zset-max-ziplist-value 64

hll-sparse-max-bytes 3000
activerehashing yes
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit slave 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
hz 10

aof-rewrite-incremental-fsync yes

      

       从Redis(Slave)配置，配置与Master类似，不一致内容如下：

#绑定IP地址
bind 192.168.1.16

#若当前服务为slave，在此处设置主服务的ip及端口
slaveof 192.168.1.18 6379

#若当前服务为slave，设置主服务的认证密码
masterauth 01130229

      配置Redis开机启动：

     [root@jhq0229 redis-stable]# vim /etc/init.d/redis

     内容如下：

#!/bin/bash
#
# redis - this script starts and stops the redis-server daemon
#
# chkconfig:   - 80 12
# description:  Redis is a persistent key-value database
# processname: redis-server
# config:      /etc/redis/redis.conf
# pidfile:     /var/run/redis.pid

source /etc/init.d/functions

BIN="/usr/local/bin"
CONFIG="/etc/redis/redis.conf"
PIDFILE="/var/run/redis.pid"


### Read configuration
[ -r "$SYSCONFIG" ] && source "$SYSCONFIG"

RETVAL=0
prog="redis-server"
desc="Redis Server"

start() {

        if [ -e $PIDFILE ];then
             echo "$desc already running...."
             exit 1
        fi

        echo -n $"Starting $desc: "
        daemon $BIN/$prog $CONFIG

        RETVAL=$?
        echo
        [ $RETVAL -eq 0 ] && touch /var/lock/subsys/$prog
        return $RETVAL
}

stop() {
        echo -n $"Stop $desc: "
        killproc $prog
        RETVAL=$?
        echo
        [ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/$prog $PIDFILE
        return $RETVAL
}

restart() {
    stop
    start
}

case "$1" in
  start)
        start
        ;;
  stop)
        stop
        ;;
  restart)
        restart
        ;;
  condrestart)
        [ -e /var/lock/subsys/$prog ] && restart
        RETVAL=$?
        ;;
  status)
        status $prog
        RETVAL=$?
        ;;
   *)
        echo $"Usage: $0 {start|stop|restart|condrestart|status}"
        RETVAL=1
esac

exit $RETVAL

 

     [root@jhq0229 redis-stable]# chmod +x /etc/init.d/redis

     [root@jhq0229 redis-stable]# chkconfig redis on

 

     补充配置，配置停止服务前同步数据到磁盘：

     [root@jhq0229 redis-stable]# vim /etc/sysctl.conf

     进行如下修改:

     vm.overcommit_memory=1

     应用修改：

      sysctl -p

    

      启动Redis:

      [root@jhq0229 redis-stable]# service redis start

     

      主从Redis的安装和配置只是配置文件不同，其他的均一样，一般主从配好就可以测试主从操作了，主server上set，从server马上就可以get到了。

     最后，奉上公司同事辛勤总结的Redis学习资料。希望可以帮到你。

     下载地址：    http://pan.baidu.com/s/1qWLV87a

     PPT内容版权归公司所有。