It should be a good background but the new features of MariaDB will obviously not be covered. And it will not help with Galera Cluster as that is completely new compared to what oracle offers. 

On Wednesday, April 15, 2015, Lukas Lehner <weblehner@gmail.com> wrote:
Hi

I will attend "MySQL for Database Administrators Ed 3.1" from Oracle University. I will take 1Z0-883 "OCP MySQL 5.6 Database Administrator" exam. I choose Oracle University because of their high quality education (did quite a lot of courses at them).

On my job I will work mainly with MariaDB and Galera Cluster. Is this exam and Oracle University course helpful for me? I have a background with classic Oracle RDBMs.

cheers