This blog post is about time synchronization with Hyper-V Integration services when you virtualize SBS 2008 server. You should never leave Hyper-V host to “force” time on servers that you virtualize and that are Active Directory servers (at least not PDC that is the root time server for a domain).
By default Hyper-V enables all Integration services components on your virtual machine but it’s better to configure your virtual machine in my case SBS 2008 server that is Active Directory server too with external NTP time source. Becouse if something goes wrong or you have wrong time on your Hyper-V host you can get in troubles when Hyper-V host will push this “bad time” into your virtual machine.
You should also know that by default on boot virtual machine get’s time from your Hyper-V host becouse of that I have writen two articles. First is about configuring your Hyper-V host that is not joined into a domain (so it does not get the right time from AD server) so it can receive the right time from NTP time source.
And the second one about setting correct values on SBS 2008 server and disabling Hyper-V integration services feature Time Synchronization.
Hope it helps…