I was thinking about how best to patch my servers (and specifically, DCs) and someone mentioned how they have 3 DCs in their domain - one of which is a "dev DC" (ie a testbed for patches before rolling out to the other 2 DCs). As a FYI, I abide by most best practises such as not running auto updates etc on servers.
Is 3 DCs in a domain a good idea? I guess this holds no FSMO roles? Also, would this need DNS on it? 3 is always a crowd they say. Also, what would happen if the two DCs (which are specified in DNS settings of member servers) go down? Would this DC be able to keep things up?
Thanks