[MySQL] 重启MySQL提示ERROR! MySQL is not running, but lock file (/var/lock/subsys/mysql)

重启MySQL数据库服务器提示ERROR! MySQL is not running, but lock file (/var/lock/subsys/mysql)，看了下MySQL数据库状态：

# service mysql status
ERROR! MySQL is not running, but lock file (/var/lock/subsys/mysql) exists

接着查看了下MySQL的错误日志看到：
/usr/sbin/mysqld: unknown option '--safe-show-database'
所以应该是my.cnf文件中配置出错了，将这行给去掉之后重启MySQL成功：

# service mysql restart
ERROR! MySQL server PID file could not be found!
Starting MySQL.. SUCCESS!
# service mysql status
SUCCESS! MySQL running (4040)

配置文件my.cnf 丢失，导致mysql服务不能启动等等故障：

[root@centos6 init.d]# service mysqld start
Starting MySQL.. ERROR! The server quit without updating PID file (/var/lib/mysql/centos6.pid).

重新拷贝正确my.cnf配置文件到/etc/目录下

[root@centos6 mysql]# cp support-files/my-large.cnf /etc/my.cnf
cp：是否覆盖"/etc/my.cnf"？ y
[root@centos6 mysql]# service mysqld start
Starting MySQL.... SUCCESS!
[root@centos6 mysql]# service mysqld status
SUCCESS! MySQL running (50035)

运行ok