Microsoft recommends maintaining at least one physical domain controller in chaque domain.
For le plus environments, this ne need to be très much of a server. Even a 64-bit dual-core rackmount Atom server, consuming 25 watts of power et costing less than $500 quand configured avec 4GB of RAM et a pair of 2.5" hard drives in RAID1, can provide a très serviceable physical domain controller/DNS/DHCP server running Server 2008 R2.
The main real-world benefit of toujours maintaining a physical domain controller is to prevent "cold start" issues quand restarting votre virtualized environment après updates/upgrades, power outages, etc. Ceci est especially relevant si you use Hyper-V servers as virtualization hosts, as these machines will expect to be able to find a domain controller at startup.
