mysql 数据页损坏解决办法

1.       故障表现。Mysqld 进程持续重启。大量的错误日志：

120906 7:29:43 InnoDB: Page checksum 4195361555, prior-to-4.0.14-form checksum 2124157186
InnoDB: stored checksum 3323954773, prior-to-4.0.14-form stored checksum 2124157186
InnoDB: Page lsn 54 139070759, low 4 bytes of lsn at page end 139070759
InnoDB: Page number (if stored to page already) 134634,
InnoDB: space id (if created with >= MySQL-4.1.1 and stored already) 0
InnoDB: Page may be an index page where index id is 0 89
InnoDB: (index "history_1" of table "zabbix"."history")
InnoDB: Database page corruption on disk or a failed
InnoDB: file read of page 134634.
InnoDB: You may have to recover from a backup.
InnoDB: It is also possible that your operating
InnoDB: system has corrupted its own file cache
InnoDB: and rebooting your computer removes the
InnoDB: error.
InnoDB: If the corrupt page is an index page
InnoDB: you can also try to fix the corruption
InnoDB: by dumping, dropping, and reimporting
InnoDB: the corrupt table. You can use CHECK
InnoDB: TABLE to scan your table for corruption.
InnoDB: See also http://dev.mysql.com/doc/refman/5.1/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.
InnoDB: Ending processing because of a corrupt database page.

2.       故障原因，这类情况一般有2种情况：mysql 服务异常关闭和硬件磁盘损坏。Innodb 自检过程中checksum与退出时不一致便会去recover，或者退出时buffer中flush到磁盘的任务未正常结束并update checksum。

3.       解决办法。首先确定出错的数据表。(index "history_1" of table "zabbix"."history")。按下面的顺序尝试。

A．进入mysql，如果mysql持续报错，但mysqld线程稳定，使用check table，optmize table 进行修复，大部分情况是失败。无响应或者ERROR 2013 (HY000): Lost connection to MySQL server during query

B．mysqld 进程不断重启（由innodb引擎发起的重启），check 和optimize 几乎无法在一个重启周期内完成。在my.cnf文件增加innodb_force_recovery=1 保证进程稳定。

4. 数据的恢复。

             Check table 和optmize 其实对innodb效果不明显，所以80%解决不了问题，数据恢复有2种情况。

A． 表数据完整，但checksum不一致，

a)         新建同结构表，engine=myisam

b)         Insert into new select * from old

c)         Alter table new type=innodb

d)         Drop table old,rename table new to old

B. 表数据丢失，这种一般是磁盘损坏，方法和上面一样，区别在于，需要去需找破坏点，找到损坏的数据页面范围，达到最小数据损失。在有主键id的情况下相对容易且损失数据更小。

5. 恢复后在配置文件中注释 innodb_force_recovery=1 ，并重启.