redis提供了一个save来备份当前数据库信息
[lihui@localhost ~]$ /usr/local/bin/redis-cli 127.0.0.1:6379> keys * (empty list or set) 127.0.0.1:6379> lpush nums 1 2 3 (integer) 3 127.0.0.1:6379> set lihui 30 OK 127.0.0.1:6379> hset lilei sex male (integer) 1 127.0.0.1:6379> keys * 1) "lilei" 2) "nums" 3) "lihui" 127.0.0.1:6379>
此时数据库里还是有一大堆东西的，完成了插入之后，一定要重启redis，下面说的文件才会update
[lihui@localhost ~]$ sudo service redis_6379 restart [sudo] password for lihui: Stopping ... Waiting for Redis to shutdown ... Redis stopped Starting Redis server...
直接命令SAVE，然后将备份文件dump.rdb放到其它地方
127.0.0.1:6379> SAVE
OK
[lihui@localhost ~]$ su Password: [root@localhost lihui]# locate dump.rdb /var/lib/redis/6379/dump.rdb [root@localhost lihui]# ll /var/lib/redis/6379/dump.rdb -rw-r--r--. 1 root root 83 Feb 23 22:43 /var/lib/redis/6379/dump.rdb [root@localhost lihui]# cp /var/lib/redis/6379/dump.rdb /home/lihui/ cp: overwrite ?.home/lihui/dump.rdb?. y
也就是说此刻原始3个key的数据库备份放在了/home/lihui下面，接着删掉一个key
[lihui@localhost ~]$ /usr/local/bin/redis-cli 127.0.0.1:6379> del lilei (integer) 1 127.0.0.1:6379> keys * 1) "lihui" 2) "nums" 127.0.0.1:6379> [lihui@localhost ~]$ sudo service redis_6379 restart Stopping ... Redis stopped Starting Redis server... [root@localhost lihui]# ll /var/lib/redis/6379/dump.rdb -rw-r--r--. 1 root root 53 Feb 23 22:47 /var/lib/redis/6379/dump.rdb
可见dump.rdb的确是update了一下，字节变小了；此时，假如想要恢复开始未del之前的3个key的数据库，只需要将备份在/home/lihui下的文件copy到redis的安装目录下
查找redis的安装目录
127.0.0.1:6379> config get dir 1) "dir" 2) "/var/lib/redis/6379"
于是直接copy
[root@localhost lihui]# cp /home/lihui/dump.rdb /var/lib/redis/6379/ cp: overwrite ?.var/lib/redis/6379/dump.rdb?. y [root@localhost lihui]# ll /var/lib/redis/6379/dump.rdb -rw-r--r--. 1 root root 83 Feb 23 22:56 /var/lib/redis/6379/dump.rdb
此刻清楚地看到文件大小是83字节，可惜无论重启redis否，依旧是del之后的数据库了，而且重启了redis后，文件大小又变成53字节了
[lihui@localhost ~]$ /usr/local/bin/redis-cli 127.0.0.1:6379> keys * 1) "nums" 2) "lihui" 127.0.0.1:6379> [lihui@localhost ~]$ sudo service redis_6379 restart [sudo] password for lihui: Stopping ... Waiting for Redis to shutdown ... Redis stopped Starting Redis server... [lihui@localhost ~]$ /usr/local/bin/redis-cli 127.0.0.1:6379> keys * 1) "nums" 2) "lihui" [root@localhost lihui]# ll /var/lib/redis/6379/dump.rdb -rw-r--r--. 1 root root 53 Feb 23 22:56 /var/lib/redis/6379/dump.rdb
这就很奇怪了，也就是备份根本没完全生效，或者是存在某种缓存机制，没有实时刷新到磁盘~！
