MariaDB, a fork of mySQL itself, bills itself as completely compatible with mySQL, so any mySQL install can be upgraded to MariaDB pretty much seamlessly (it was trivial for me using apt-get on Ubuntu). The arguments for MariaDB over mySQL include:
- More open source commitment from MariaDB than mySQL, especially after mySQL’s purchase last year by Oracle.
- Better performance as your database application scales.
- Better features.
I haven’t found any noticeable advantages yet on my small WordPress site, but I do worry about the direction of mySQL under Oracle, and it does seem that many important organizations, even Google, have made the switch. I can see MariaDB becoming the standard over mySQL for mySQL-ish installations.
What I do see is that the folks at MariaDB have done a wonderful job keeping it compatible with mySQL. If you know and are comfortable with mySQL, you won’t notice many differences, if any, working with MariaDB. If you know mySQL, you know MariaDB, and your existing databases will “just work”.
You might as well give it a spin.