tarting MySQL. ERROR! The server quit without updating PID file

[chaitanya D]

Created user - mysql and group mysql
mount point /data owned by mysql
chown -R mysql:mysql /data


Installed RPM - 'MySQL-server-advanced-5.6.24-1.el6.x86_ , client and shared also '

Able to start and login and changed the root password .

Stop the MYSQL moved /var/lib/mysql contents to /data
edited my.cnf file
datadir = /data

After when i start mysql i run in to problems . if i comment datadir in my.cnf file its working fine .

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Scenario -2

Before installing RPM edited my.cnf file (datadir =/data) then installed the rpms the files and folders are created but the errorlog file is not created and facing the same problem while starting the mysql



Any suggestions why mysql is not able to create the pid file