* mysql启动报错时
        重启时    /etc/init.d/mysqld restart
                 Stopping mysqld:                                           [  OK  ]
                 Another MySQL daemon already running with the same unix socket.
                 Starting mysqld:                                           [FAILED]
        删除文件  rm -fr /var/lib/mysql/mysql.sock
        重启mysql /etc/init.d/mysqld restart
                 Stopping mysqld:                                           [  OK  ]
                 Starting mysqld:                                           [  OK  ]

Another MySQL daemon already running with the same unix socket.