MySQL manager or server PID file could not be found!

 [root@centos var]# service mysqld stop

MySQL manager or server PID file could not be found!        [FAILED]

解决办法：

首先查看一下进程

[root@centos mysql]# ps aux |grep mysq*

root       2643   0.0   0.2    4536   1224 ?         S     01:09    0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/usr/local/mysql/var --pid-file=/usr/local/mysql/var/centos.pid

mysql      2757   0.0   1.2   36976   6608 ?         Sl    01:09    0:00 /usr/local/mysql/libexec/mysqld --basedir=/usr/local/mysql --datadir=/usr/local/mysql/var --user=mysql --log-error=/usr/local/mysql/var/centos.err --pid-file=/usr/local/mysql/var/centos.pid --socket=/tmp/mysql.sock --port=3306

root       4788   0.0   0.1    3920    684 pts/2     R+    11:11    0:00 grep mysq*

如果看到上面的内容，那说明， Mysql 的进程卡死了，这时用就要把这些卡死的进程都关闭

[root@centos mysql]# kill 2643

[root@centos mysql]# kill 2757

启动 Mysql 就 ok 了

[root@centos mysql]# service mysqld start

Starting MySQL.                                             [   OK   ]