Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

Consider a domain controller running Windows Server 2008 R2 with a dual-port NIC. Would I encounter problems by installing the Hyper-V role? Here are my primary concerns:

  • Because Hyper-V is a hypervisor, the parent OS is also a virtual machine, it just happens to be in a special partition. Would the timekeeping problems associated with virtual machines apply in this instance?
  • One GigE port would be dedicated to Hyper-V, the other would be used for the parent partition. I've heard all about DHCP weirdness with Hyper-V on a DC. Can this be avoided as long as it is carefully configured?

We will be getting a new server for use as a DC in a few weeks, and for only the cost of increased RAM, it could serve as a decent virtualization platform.

(Edit: This won't be the only DC for the domain, but I will be moving all of the FSMO roles onto it, making our existing DC act only as a secondary.)

share|improve this question

2 Answers 2

up vote 2 down vote accepted

Just to be clear, the "parent partition" on the virtual host, regardless of whether you want to technically refer to it as a VM or not, would not have the same issues with timekeeping. If you do end up deciding to instead run AD on a normal VM that actually appears in Hyper-V manager, be careful about how you manage it: 1) don't ever take snapshots of that VM because they are worthless on a DC and reverting to one of them will cause lots of trouble, and 2) don't expect to have the same flexibility with reverting to a backup of that VM either (in the way that you could with another box like a web server). More on these issues here: http://support.microsoft.com/kb/888794. As has been previously mentioned, the best config is to run these roles (Hyper-V and DC) on separate boxes.

share|improve this answer
    
I chose this answer because you convinced me that the Hyper-V role should not be installed on a domain controller. (But could you explain why it won't have timekeeping issues?) –  Nic Feb 26 '10 at 2:13
    
I believe the parent partition has direct access to the hardware clock, as it is providing a (virtual) clock for all other VMs. –  fission Feb 28 '10 at 5:27
    
@Nic -- this is an old question which showed up in my feed, but thought I'd drop a comment anyway. The time sync issues with Hyper-V occur because the virtualisation layer offers a time sync service to VMs to allow them to sync time with the host server, which may cause skew with the "authoritative" source of time on the network (such as hosted at the forest root PDC emulator). Since this service isn't offered to the "parent partition" of a Hyper-V host, you won't get the weird time skewness. –  Cosmic Ossifrage Jun 30 at 22:59

If you very carefully configure your DHCP so that you're only offering that service on NICs that are not also in use as virtual switches, you won't have any problems in that realm.

But Hyper-V is designed as a standalone single roll. You should consider running your domain controller inside a VM, instead.

share|improve this answer
    
+1 for confirming that DHCP would work in this scenario. –  Nic Feb 26 '10 at 2:10

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.