Any limits to the number of chat rooms

Hi,

I'm working on a production ejabberd deployment that is having a few performance issues. The server has tens of thousands of persistent muc rooms, but at any given time the majority of them don't have any users in the room. My instinct is that these empty rooms won't have an impact on the performance of the system but would love for someone to give me a definitive answer so I can rule this out as a possible cause of the performance problems.

Thanks in advance.

--Ryan