As usual a good conversation spurred on ActiveDir on a much discussed scenario of virtualizing your DCs while be varied of the known pitfalls. While virtualized DCs are fully supported on either competing virtualization solution by Microsoft, one known subject I would like to highlight here is the proper time synchronization. You must make sure that your PDCe gets its time from an external time source and other DCs follow the PDCe. All DCs (including PDCe) must not sync their time with the virtualization host, whether its VMware ESX or that of Hyper-V. It was discussed how by default the VMware’s VM settting does not have the time synchronization enabled by default, and my brief look at the Hyper-V’s VM suggested that it is. In any case, you must make sure that setting is disabled, thus VM does sync its time with its host.
VMware time setting from the VMware tools within the VM:
Or under the VM settings from VIC :
Hyper-V setting from the VM settings :
A great resource to refer to, to learn how to configure an authoritative time source for your DCs – see this KB http://support.microsoft.com/kb/816042