mysql遇见问题记录

mysql

问题记录：

service mysql start 显示错误信息：

140207 14:30:33 [Note] Plugin 'FEDERATED' is disabled.
mysqld: Can't find file: './mysql/plugin.frm' (errno: 13)
140207 14:30:33 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
140207 14:30:33 InnoDB: The InnoDB memory heap is disabled
140207 14:30:33 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140207 14:30:33 InnoDB: Compressed tables use zlib 1.2.3.4
140207 14:30:33 InnoDB: Initializing buffer pool, size = 128.0M
140207 14:30:33 InnoDB: Completed initialization of buffer pool
140207 14:30:33  InnoDB: Operating system error number 13 in a file operation.
InnoDB: The error means mysqld does not have the access rights to
InnoDB: the directory.
InnoDB: File name ./ibdata1
InnoDB: File operation call: 'open'.
InnoDB: Cannot continue operation.

• 原因：

ubuntu下，mysql默认数据库存放路径是 /var/lib/mysql,由于管理员在 /etc/mysql/my.cnf 重定义了 datadir 但是 /data/mysql 没有设置正确的权限，重置 chown -R mysql:mysql /data/mysql 权限后，服务启动正常

• 注意：
  如果更改了 /etc/mysql/my.cnf 的配置， /etc/apparmor.d/usr.sbin.mysqld 中也添加相应配置

#datadir        = /var/lib/mysql
datadir         = /data/mysql

/etc/apparmor.d/usr.sbin.mysqld

/var/log/mysql/ r,
/var/log/mysql/* rw,