How can I upgrade from MySQL to MariaDB?

For all practical purposes, you can view MariaDB as an upgrade of MySQL:

• Within the same base version (for example 5.1) you can just uninstall MySQL and install MariaDB and you are good to go. There is no need to dump and restore databases. As with any upgrade, we recommend making a backup of your data beforehand.
• If MariaDB has a higher main version number, you should run mysql_upgrade (just as you would with MySQL) to finish the upgrade.
• All your old clients and connectors (PHP, Perl, Python, Java, etc.) will work unchanged (no need to recompile). This works because MariaDB and MySQL use the same client protocol and the client libraries are binary compatible.

You can find more information on the MariaDB installation page.