[Rdo-list] Ceilometer DB?

Hi Y'all, I was going to try and set up Ceilometer using MySQL as a DB backend on my test cluster, but I had read somewhere that MySQL wasn't supported as a database backend with Ceilometer under RDO yet. I just wanted to confirm, is that true? Am I required to use MongoDB? Just checking before I go through a bunch of debugging just to learn that "it doesn't work anyway..." ;) cheers, erich