Hi All, I've recently received two relatively beefy servers to replace all four of our current servers. I'm using Windows Server 2008 R2 and I've added the Hyper-V role to both servers. One of the host machines is now our domain controller and I was planning on having a virtual machine on the second new server as a backup domain controller. I know times have changed and the roles of "primary" and "backup" DC's are (apparently) not really relevant. Even though all our international sites are connected via a private MPLS, each site is on a different subnet on the same domain. Since we're the newest site, I've only ever had one DC on site. I had the idea of setting up the second (low resource VM) DC as an RODC. The idea is, if the first DC is down for any reason, users would still be able to log on by querying the RODC VM. Is there any merit in doing this? I understand the concept of RODC's tackling the "branch office" setup, but would an RODC work as a backup domain controller on the same site as well?

OK, thanks to both of you. These are the answers I was looking for. I wasn't really aware of the limitations, I just kept coming across the branch scenarios in my research. Standard DC seems to be the answer then!