HI,
Some time we are getting this error while starting/restarting MySQL service. It's because of MySQL data directory is not set correctly or MySQL data directory's path has changed. When you look in to the /var/log/mysqld.log file you can see the following errors:
=================>>>
/usr/libexec/mysqld: Table 'mysql.plugin' doesn't exist
120907 5:04:43 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
120907 5:04:43 InnoDB: Initializing buffer pool, size = 8.0M
120907 5:04:43 InnoDB: Completed initialization of buffer pool
120907 5:04:43 InnoDB: Started; log sequence number 0 44233
120907 5:04:43 [ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.host' doesn't exist
120907 05:04:43 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
=================>>>
Now, you need to find our what is correct path of MySQL data directory, it's very simple. You can get this information with the help of this command:
=================>>>
root@www ~]# whereis mysql
mysql: /usr/bin/mysql /usr/include/mysql /usr/share/mysql /usr/share/man/man1/mysql.1.gz
[root@www ~]#
=================>>>
You can see that the MySQL data directory path is showing "/usr/include/mysql", you need to configure your MySQL configuration file accordingly. Open MySQL configuration file via VIM editor and change/add "datadir" directory.
=================>>>
#vim /etc/my.cnf
datadir=/usr/include/mysql
=================>>>
You have done now, please restart MySQL service and check this. I am sure it will start without any errors.
Enjoy:-
Thank you,
