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
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