ERROR! MySQL manager or server PID file could not be found!

Error :- You may get ERROR! MySQL manager or server PID file could not be found! when starting MySQL service.

Cause :- Existing PID doesn't allow to create new PID.

WorkAround:- Kill the old PID and then start MySQL service.

Step 1-  

Check MySQL existing PID  using command :-   ps -aufx | grep mysql

 

[root@cent ~]# ps -aufx | grep mysql
Warning: bad syntax, perhaps a bogus '-'? See /usr/share/doc/procps-3.2.7/FAQ
root     10075  0.0  0.0  61304   748 pts/0    S+   00:31   0:00                      \_ grep mysql
root      4723  0.0  0.0  65948  1312 ?        S    Mar13   0:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --pid-file=/var/lib/mysql/cent.pid
mysql     4816  0.0  2.1 288868 85376 ?        Sl   Mar13 198:35  \_ /usr/sbin/mysqld --basedir=/ --datadir=/var/lib/mysql --user=mysql --log-error=/var/lib/mysql/cent .err --pid-file=/var/lib/mysql/cent.pid

In above query, we found two Existing PID.

Step 2 - 

Let's kill them using kill command. 

[root@cent ~]# kill -9 4723
[root@cent ~]# kill -9 4816

Step 3- 

Now start MySQL service.

[root@cent ~]# /etc/init.d/mysqld start
Starting MySQL...... SUCCESS!

Step 4 -

Let's Check MySQL service Status.

[root@cent ~]# /etc/init.d/mysqld status
 SUCCESS! MySQL running (14346)
[root@cent ~]#

MySQL service has been restarted successfully 

That's All

!!!Cheers!!!