MySQL Daemon Failed to Start - centos 6

Question

EDIT: Look at the checkmarked answer comments to get your issue solved.

Whenever I try to start the SQLD service I get MySQL Daemon Failed to Start. I infact tried

Answer 1

Reference here 2.10.2.1 Troubleshooting Problems Starting the MySQL Server.

1.Find the data directory ,it was configured in my.cnf.

[mysqld]
datadir=/var/lib/mysql

2. Check the err file,it log the error message about why mysql server start failed. the name of err file is related with your hostname.

cd /var/lib/mysql
ll
tail (hostname).err

3.If you find some messages like :

InnoDB: Error: log file ./ib_logfile0 is of different size 0 33554432 bytes
InnoDB: than specified in the .cnf file 0 5242880 bytes!
170513 14:25:22 [ERROR] Plugin 'InnoDB' init function returned error.
170513 14:25:22 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
170513 14:25:22 [ERROR] Unknown/unsupported storage engine: InnoDB
170513 14:25:22 [ERROR] Aborting

then

delete ib_logfile0 and ib_logfile1

, then,

/etc/init.d/mysqld start