Hi there I saw the other post first but I replied in both places, sorry
One of the problems with something like this is that many people call them different things.
1. Dressing Room and Locker Room both work. It's obviously not a locker room if you don't have lockers.
2. We call it a "server farm" at work but that's colloquial. "Data Center" is a more appropriate term for that room.
3. Board Room works