我有一个 Web 服务器，其中 mysql 的默认安装将其所有数据库文件放在/var/lib/mysql. 分区所在/var挂载只有2GB的空间，所以在运行出现空间问题后，我决定重新定位mysql的数据目录。
我天真的方法是将/var/lib/mysql目录完全复制到/web/dbs/mysql，然后更改/etc/mysql/my.cnf以使其读取
datadir = /web/dbs/mysql
但是，重启后，我在mysql错误日志中得到以下错误，并且服务器无法启动。
130130 9:59:23 [Note] Plugin 'FEDERATED' is disabled.
/usr/sbin/mysqld: Can't find file: './mysql/plugin.frm' (errno: 13)
130130 9:59:23 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
130130 9:59:23 InnoDB: Initializing buffer pool, size = 8.0M
130130 9:59:23 InnoDB: Completed initialization of buffer pool
130130 9:59:23 InnoDB: Operating system error number 13 in a file operation.
InnoDB: The …