Virtualizing domain controllers
The last best practice I want to give you is about moving special workloads to Hyper-V. After having done many P2V migrations, there are only two workloads that deserve the attribute special: a small business server and a domain controller. The first one is very simple—don't try to convert small business servers, they are outdated. Create a new virtual machine and rebuild the services offered by SBS with the current products. If you get rid of the SBS server in the process, every IT person will love you.
The second one deserves special consideration. Is it a good idea to virtualize domain controllers? Absolutely, they are built for it. Should you convert physical domain controllers? If you have to, you can do it. Often, it is faster to just deploy a new DC to the existing domain and remove the old one after that from the domain.
Should you virtualize all your domain controllers? Absolutely not. Domain controllers run great in virtual machines; however...
