相对于 MySQL,redis 基于内存操作可提供较好的速度体验,并且也可以提供持久化存储,数据类型丰富,存取方便,作为缓存,值得使用。
Redis is an in-memory database that persists on disk. The data model is key-value, but many different kind of values are supported: Strings, Lists, Sets, Sorted Sets, Hashes, HyperLogLogs, Bitmaps.
安装
cd /home/tools
wget http://download.redis.io/releases/redis-3.2.4.tar.gz
tar xzf redis-3.2.4.tar.gz
cd redis-3.2.4
make
make PREFIX=/usr/local/redis install
make PREFIX=/usr/local install
make PREFIX=/usr install
cp redis.conf /usr/local/redis/redis_example.conf
- make 后,即可运行编译好的文件;
src/redis-server
src/redis-client
- make [PREFIX=/some/other/directory] install 安装到指定目录;
默认安装在 /usr/local/bin 下;
redis.conf 配置 片段
dir /var/lib/redis/
slave-read-only yes
- dir 指定持久化数据存放目录 /var/lib/redis/;
- slaveof 配置后,表明这个 redis 实例是一个 slave,运行在 slave 状态;
- 访问 slave 时,假如 slave 设置为 slave-read-only,那么访问方式;
- 配置文件存放到 /etc/ 下,或者 /usr/local/redis/ 下;
- 配置文件命名 redis_6379.conf,6379 是服务端口;
- bind 指令指定本机(127.0.0.1)和内网地址(192.168.*.*,通常不要对外开放 redis 服务)
当你没有使用 bind 指令(也就是绑定所有网络地址),也没有设认证密码时,你只能在本机访问该服务;
(error) DENIED. Redis is running in protected mode because protected mode is enabled, no bind address was specified, no authentication password is requested to clients. In this mode connections are only accepted from the loopback interface. If you want to connect from external computers to Redis you may adopt one of the following solutions: 1) Just disable protected mode sending the command 'CONFIG SET protected-mode no' from the loopback interface by connecting to Redis from the same host the server is running, however MAKE SURE Redis is not publicly accessible from internet if you do so. Use CONFIG REWRITE to make this change permanent. 2) Alternatively you can just disable the protected mode by editing the Redis configuration file, and setting the protected mode option to 'no', and then restarting the server. 3) If you started the server manually just for testing, restart it with the '--protected-mode no' option. 4) Setup a bind address or an authentication password. NOTE: You only need to do one of the above things in order for the server to start accepting connections from the outside.
- 机器变更内网 ip 地址时,注意更改 redis.conf 文件,并重启服务;
启动停止
- 启动
redis-server /usr/local/redis/redis_6379.conf
redis-server /usr/local/redis/redis_6380.conf
- 关闭
redis-cli 进入交互界面,shutdown
即可;
持久化
- 了解 CAP 定理(CAP theorem)
Consistence、Availability、Partition tolerance;
Master/Slave Replication 复制工作原理
- slave 启动时,连接上 master,发送 PSYNC 命令;
- master 接到命令,启动一个后台进程保存数据到 rdb 文件;
- master 和 slave 之间传送 rdb 文件;
- slave 将文件加载到内存;
- 初始文件数据传送完毕之后的传送就是命令流了;
- slave 支持重连;重连之后就只传送增量内容了(partial resynchronization);
slave configuration
- 选项:
slaveof 192.168.1.1 6379
在 slave 的配置文件中,使用 slaveof 指定 master 的 ip & port 即可;
通过命令行slaveof <ip> <port>
命令可临时连接指定的 master; - 选项:
slave-read-only yes
yes 是默认设置; - masterauth <password>
如果 master 通过 requirepass 设置了认证,则 slave 可通过 masterauth 给出认证需要的密码;
通过命令行:config set masterauth <password>
可临时设置;
redis-cli
redis-cli -p 6380
- 查看库2中没有设置过期的keys;
redis-cli -n 2 keys '*' | while read LINE ; do TTL=\
redis-cli -n 2 ttl $LINE`; if [ $TTL -eq -1 ]; then echo "$LINE"; fi; done;`
Redis Administration
- set the Linux kernel overcommit memory setting to 1
echo vm.overcommit_memory = 1 >> /etc/sysctl.conf
sysctl vm.overcommit_memory=1
立即生效;
redis命令介绍
- redis-benchmark:性能测试工具
- redis-check-aof:数据修复
- redis-check-dump:检查导出工具
- redis-check-rdb:
- redis-cli:命令行工具;提供交互操作界面;
-n 指定 database number; - redis-sentinel
- redis-server:服务程序;
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