一.redis介绍
redis是一个key-value存储系统,与memcached类似,但是解决了断电后数据完全丢失的现象。支持数据类型有string,lists,sets,zsets。这些数据类型都支持push/pop,add/remove以及取交集并集差集等操作,对这些操作都是原子性的,redis还支持各种不同的排序能力。
二.redis安装
$ sudo wget http://redis.googlecode.com/files/redis-2.2.12.tar.gz
$ sudo tar zxvf redis-2.2.12.tar.gz -C ../software/
$ sudo cd /usr/local/src/software/redis-2.2.12/src
$ sudo make PREFIX=/usr/local/redis-2.2.12
$ sudo make test
Testing Redis version 2.2.12 (00000000)
831 tests, 831 passed, 0 failed
$ sudo make PREFIX=/usr/local/redis-2.2.12 install
常见错误:
(cd ..; tclsh8.5 tests/test_helper.tcl –tags “” –file “”)
/bin/sh: tclsh8.5: not found
make: *** [test] Error 127
解决方法:
$ sudo apt-get install tcl8.5
三.redis配置
$ sudo mkdir -p /usr/local/redis-2.2.12/{etc,var}
redis-server:redis服务的启动程序
redis-cli:redis命令行操作工具
redis-benchmark:redis性能测试工具
redis-check-aof:更新日志检查
redis-check-dump:本地数据检查
$ sudo cp redis.conf /usr/local/redis-2.2.12/etc/
redis.conf配置参数说明:
daemonize //是否以后台进程运行,默认为no
pidfile /var/run/redis.pid //pid文件路径
port 6379 //监听端口
bind 127.0.0.1 //绑定主机ip
unixsocket /tmp/redis.sock //sock文件路径
timeout 300 //超时时间,默认是300s
# 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)
loglevel verbose //日志等级,可选项有debug,verbose,notice,warning 默认是erbose
logfile stdout //日志记录方式,默认是stdout
syslog-enabled no //日志记录到系统日志中,默认是no
syslog-ident redis //指定系统日志标识
# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
syslog-facility local0 //指定系统日志设备,默认是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
databases 16 //可用数据库数,默认值是16,默认数据库是0
save <seconds> <changes> //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。
save 900 1 //15min内至少1个key被改变
save 300 10 //5min内至少有300个key被改变
save 60 10000 //60s内至少有10000个key被改变
rdbcompression yes //存储至本地数据库时是否压缩数据,默认是yes
dbfilename dump.rdb //本地数据库文件名,默认是dump.rdb
dir ./ //本地数据库存放路径,默认是./
slaveof <masterip> <masterport> //当本机为从服务时,设置主服务的ip以及端口
masterauth <master-password> //主服务的连接密码
# When a slave lost the connection with the master, or when the replication
# is still in progress, the slave can act in two different ways:
#
# 1) if slave-serve-stale-data is set to ‘yes’ (the default) the slave will
# still reply to client requests, possibly with out of data data, or the
# data set may just be empty if this is the first synchronization.
#
# 2) if slave-serve-stale data is set to ‘no’ the slave will reply with
# an error “SYNC with master in progress” to all the kind of commands
# but to INFO and SLAVEOF.
#
slave-serve-stale-data yes
requirepass foobared //连接密码foobared
maxclients 128 //最大连接数,默认不限制
maxmemory <bytes> //设置最大内存,达到最大内存设置后,redis会先尝试清除已到期或即将到期的key,当此方法处理后,任然到达最大内存设置,将无法再进行写入操作
maxmemory设置策略
# volatile-lru -> remove the key with an expire set using an LRU algorithm
# allkeys-lru -> remove any key accordingly 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
maxmemory-policy volatile-lru //maxmemory设置策略,默认是volatile-lru.
maxmemory-samples 3
appendonly no //是否 在每次更新操作后进行日志记录,如果不开启,可能会在断电时导致一段时间内的数据丢失。因为redis本身同步数据文件是按照上面save条件来进行同步的,所以有的数据会在一段时间内只存在于内存中。默认是no
appendfilename appendonly.aof //更新日志文件名,默认是appendonly.aof
redis支持的三种不同的同步方式:
# no: don’t fsync, just let the OS flush the data when it wants. Faster. //等待OS进行数据缓存同步到硬盘
# always: fsync after every write to the append only log . Slow, Safest. //每次更新操作后调用fsync()将数据写到磁盘
# everysec: fsync only if one second passed since the last fsync. Compromise. //每秒同步一次
appendfsync everysec //更新日志条件,默认是everysec
no-appendfsync-on-rewrite no
slowlog-log-slower-than 10000 //设置redis slow log时间,只包括命令执行时间,不包括IO操作时间,比如客户端连接,应答相应时间等等。单位是microseconds(一百万分之一秒),默认是10000.负值表示禁用slow log,0表示记录所有命令。
slowlog-max-len 1024 //slowlog最大长度1024.这会消耗内存,使用SLOWLOG RESET来回收slowlog内存。
#在redis2.4版本,强烈不建议使用virtual memory。
vm-enabled no //是否使用虚拟内存,默认是no
vm-swap-file /tmp/redis.swap //虚拟内存文件路径,默认是/tmp/redis.swap,不可多个redis实例共享虚拟内存文件。
vm-max-memory 0 //设置最大vm,默认为0,所有的value存在于磁盘中。
vm-page-size 32 //设置vm的page大小,默认是32
vm-pages 134217728 //设置swap文件中最大memory pages,默认是134217728。swap大小=vm-page-size * vm-pages
vm-max-threads 4 //vm同时运行的最大io线程
#指定在超过一定的数量或者最大的元素超过某一临界值时,采用一种特殊的哈希算法
hash-max-zipmap-entries 512 //配置字段最多512个
hash-max-zipmap-value 64 //配置value最大为64字节
list-max-ziplist-entries 512
list-max-ziplist-value 64
set-max-intset-entries 512
activerehashing yes //是否重置hash表
include /path/to/other.conf //引用其他配置文件
$ sudo vim /etc/sysctl.conf
vm.overcommit_memory = 1 //指定内核针对内存分配的策略,其值可以是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
$ sudo sysctl -p
$ sudo vim redis.conf
daemonize yes
pidfile /var/run/redis.pid
port 6379
timeout 300
loglevel verbose
logfile /usr/local/redis-2.2.12/var/log/redis.log
databases 16
save 900 1
save 300 10
save 60 10000
rdbcompression yes
dbfilename dump.rdb
dir /usr/local/redis-2.2.12/var/data
appendonly no
appendfsync everysec
no-appendfsync-on-rewrite no
slowlog-log-slower-than 10000
slowlog-max-len 1024
vm-enabled no
vm-swap-file /tmp/redis.swap
vm-max-memory 0
vm-page-size 32
vm-pages 134217728
vm-max-threads 4
hash-max-zipmap-entries 512
hash-max-zipmap-value 64
list-max-ziplist-entries 512
list-max-ziplist-value 64
set-max-intset-entries 512
activerehashing yes
启动:
$ sudo /usr/local/redis-2.2.12/bin/redis-server /usr/local/redis-2.2.12/etc/redis.conf
四.测试
$ cat /etc/passwd | ./redis-cli -x set mykey
OK
$ ./redis-cli get mykey
“root:x:0:0:root:/root:/bin/bashdaemon:x:1:1:daemon:/usr/sbin:/bin/shmysql:x:111:120:MySQL Server,,,:/var/lib/mysql:/bin/false”