How much more resources (if any) will a full blown Windows 2008 R2 Server running just the Hyper-V role take over Microsoft Hyper-V Server 2008 R2?
I've had conversations with the Windows Team and the difference between the two isn't so much in resources, it's in security and licencing. A full Windows Server 2008 R2 with Hyper-V only and less then a dozen VM's shouldn't need more then .5 GB of RAM for host/parent OS, Up to 1GB if you're running more, and I've never seen a "stock" host OS affect performance in any way... that is until till people do stuff on the parent OS like add backup agents, AV agents, monitoring agents, etc. which will happen the same when you do that in Hyper-V server or server core.
In my conversations with SMB clients and enterprises about the decision of "Hyper-V Server" vs. "Windows Server" the questions we use to help make the decision are never really about performance in this world of 16 core's and 128GB of RAM.:
- do you admins have skills in supporting Servers without GUI's (i.e. wmi, powershell, etc. as this tends to be the single biggest factor that moves most shops to buying full Windows Server, they don't have time to train staff how to manage servers remotely or through cmd line)
- do you have specific security requirements that justify the need for Server Core (security office mandates it for any virtualization platform to reduce risk of jailbraking into guests)
- do you need features that would require a full Windows Server OS (does all your add-on management software support the server-core GUI-less console of Hyper-V server)
- Is your licencing setup where you need to run Windows Server Enterprise on the parent OS in order to take advantage of the 4 included guest OS licenses (or Datacenter for unlimited guests)
I know this doesn't specifically answer your question, but if the answer was "hyper-v 300MB" and "Windows Server 500MB" then I didn't want you to take that as a decision to pick one over the other.