Starting MySQL.The server quit without updating PID file (/var/lib/mysql/xxxxxx.pid).
Sometimes, you server throw errors like..
Starting MySQL. The server quit without updating PID file (/var/lib/mysql/xxxxxx.pid)
These kind of server errors occurs when there is a problem with your /etc/my.cnf file.
To rectifiy such kind of Mysql server errors, you need to create the /etc/my.cnf file.
Here is the command to create the my.cnf file:
cp /usr/share/mysql/my-small.cnf /etc/my.cnf
Now, create the file and try to restart the MySQL database again.
Here is the cPanel Mysql upgradation tutorial