新安装的一台CentOS服务器，安装完LAMP后，重启了一下系统，发现MySQL启动不了并报如下的错误：
/etc/init.d/mysqld startStarting MySQL... ERROR! The server quit without updating PID file (/var/lib/mysql/feixiag.pid).
查看日志如下：InnoDB: Apply batch completed
2015-03-18 17:28:05 24592 [Note] InnoDB: 128 rollback segment(s) are active.
2015-03-18 17:28:05 24592 [Note] InnoDB: Waiting for purge to start
2015-03-18 17:28:05 24592 [Note] InnoDB: 5.6.21 started; log sequence number 1600607
2015-03-18 17:28:05 24592 [Note] Server hostname (bind-address): '*'; port: 3306
2015-03-18 17:28:05 24592 [Note] IPv6 is available.
2015-03-18 17:28:05 24592 [Note] - '::' resolves to '::';
2015-03-18 17:28:05 24592 [Note] Server socket created on IP: '::'.
2015-03-18 17:28:05 24592 [ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.user' doesn't exist
150318 17:28:05 mysqld_safe mysqld from pid file /var/lib/mysql/feixiag.pid ended
google,百度后，也没有找到好的方法，突然想起，我在初始化数据库的时候指定了datadir的路径为/data/mysql，而在/etc/my.conf中的datadir没有修改指定的路径。
查看/etc/my.conf，果然是没有更改，改为datadir=/data/mysql 后，启动成功。