The founders and web developers of MySQL resigned from their native company which belongs to Oracle (once Sun consumed MySQL and later Oracle consumed Sun).
Maria combines Percona and Google patches, thus being the most optimized engine integrating the best of both.
Database management system MariaDB is a fork of MySQL, and was developed by Monty Program Ab Company founded by Michael “Monty” Widenius after he left Oracle/Sun Microsystems. MariaDB 5.1.x. is completely compatible with MySQL 5.1.x that allows a migration from MySQL to MariaDB happen without any compatibility problems.
Rumors spread that Oracle “kills” MySQL, so the main task is classical – to leave it behind in time.
We tested it many times, checking its work on sites with high load. The results turned out to be impressive. As a result – we switched Chiq.com site into the new engine and enjoyed it a lot!
We liked a new babe base and we are going to switch over to it.
UPD: in no time Maria appeared in Drupal development requirements - https://www.drupal.org/docs/system-requirements