When I type mysql, it shows “ERROR 2002 (HY000): Can’t connect to local MySQL server through socket ‘/var/run/mysqld/mysql.sock’ (2)”.

Then I try to start mysql service:

$ service mysql start

But then I get error “

No directory, logging in with HOME=/

……

MySQL Community Server 5.6.27 did not start. Please check logs for more details.

“

Then I try to find the log file. It’s located in /var/lib/mysql/bejond.err

Then I look at the log file and locate

“

InnoDB: No valid checkpoint found.

InnoDB: If this error appears when you are creating an InnoDB database,

InnoDB: the problem may be that during an earlier attempt you managed

InnoDB: to create the InnoDB data files, but log file creation failed.

InnoDB: If that is the case, please refer to

InnoDB:http://dev.mysql.com/doc/refman/5.6/en/error-creating-innodb.html

“

Then I go to the link, find the note, if the error happends on start mysql,  delete all files      created by InnoDB: all      ibdata files and all      ib_logfile files.

So I delete /var/lib/mysql/ibdata1, ib_logfile0, ib_logfile1. Then restart the service. It works!