For Red Hat Linux, the MySQL server is off by default. To turn it on, however, is fairly simple. The /etc/init.d/mysqld start-up script is delivered with the mysql-server package. To start the server, you can either run the mysqld start-up script manually or set it to start each time your system boots.
To start the MySQL server manually, type the following from a Terminal window as root user:
# service mysqld start
To have the MySQL server start each time the computer reboots, type the following (as root):
# chkconfig mysqld on
This sets mysqld to start during most multiuser run states (levels 3, 4, and 5). To check that the service is turned on for those levels, type chkconfig --list mysqld from a Terminal window.