SCVMM, choose your CPU Type wisely
Posted by Wiebe Niehof in Server 2008, System Center, VirtualizationA few months ago my beloved colleague Walter gave me the Beta version of System Center Virtual Machine Manager. Unfortunately I haven’t had the time to play with it until now. While most people enjoy their well earned vacation, I’m playing around with SCVMM.
There are definitely things to be excited about:
- Ability to manage both Hyper-V and VMware farms
- Migrate virtual machines between Hyper-V hosts (maybe not a live migration, but a migration none the less! )
- But the main thing to be excited about is the future integration within the System Center family.
And their are also some irritating things:
- Hyper-V has just RTM’ed and SCVMM is still in beta. This means you got to install update after update to make everything work.
- When I try to install the integration services on Windows Vista it comes with the message: “Unsupported Guest OS – An error has occurred: The specified program requires a newer version of Windows.” Unfortunately I’m not yet in the possession of Windows 7…
- I created a new library share. But when I try to mount an ISO file to my virtual machine it fails and the only thing you can do with your virtual machine from that point is remove it and repair it. Through the repair option you can save him by the way.
I properly can go on and on with these things but I can rather posts these on connect.microsoft.com. It is still a beta and I believe eventually these ‘minor’ issues will be solved.
There is one very interesting feature I found in SCVMM and I’m still not sure if it’s a brilliant or stupid thing. When you create a new virtual machine you got to choose your processor type. Not just the number of virtual processors or the clock rate, no actually the processor type. Like the 1.2 Ghz Athlon, the 3.0 Ghz Pentium 4 (HT Technology) or the 2.8 Ghz Xeon MP.
It states that it uses this info to determine the processor requirements of the virtual machine. That’s being used when calculating host ratings and when setting CPU resource allocations.
You can view the host rating when you create a new virtual machine. The host rating helps you to choose the best host for your virtual machine. Based on free resources.
CPU resource allocation is something we know from VMware ESX. VMware uses shares to do this. A plain number like 1000 or 2000. The virtual machine with 2000 shares gets twice the amount of CPU cycles (when needed) in comparison with the machine that has 1000 shares.
I understand that SCVMM should use his own system that can be plotted on all the different virtualization platforms it’s going to manage (Hyper-V, XEN, ESX). But I don’t understand how a 2.4 Ghz Opteron relates to a 2.4 Ghz Xeon.
So if I just want my production server to have a 50% preference over my test server which should I choose? And what’s worse, if I’m in doubt with this option, how about a self service user that’s got the option to create a new virtual machine? I can imagine it would properly mean that this user got the advise to skip it.
But there is one more thing confusing about this. When you use the Virtual Machine Manager snap in, there is another way to set the processor weight and you can use a simple number!

So if I change the processor type in SCVMM of a virtual machine, you would suspect something to change within this screen. But it doesn’t… Neither does it the other way around.
I’m going to investigate some more but if you got some tips or hints, please post them!





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hi,
great article. i think that the cpu type has something to do with the way the hyper-v will handle cpu calls.
or that they can easely integrate all the hypervisors.
but it still doesnt make sense for me, cool that you already had time to play with it.
keep us posted
Thanks for the article. I have been testing SCVMM beta as well. I\’m not sure what type of processor to choose and what effect this will have on the VM in the future.
I have run into a couple of other issues.
SCVMM (still in beta) can be used with Hyper-V to migrate a physical server to a virtual server. I experienced a couple of interesting situations using it.
1. After migrating a Windows 2003 SP1 32 bit Server to a virtual machine, Microsoft Integration Services would not install. It kept terminating with an error message “The specified program requires a newer version of Windows.” Upgrading the OS to SP2 fixed the issue.
Then I found this info:
Integration Services for the following operating systems:
•Windows Server 2008 (x86-based and x64-based editions)
•Windows Server 2003 Service Pack 2 (SP2) (x86-based and x64-based editions)
•Windows 2000 Server Service Pack 4 (SP4)
•Windows Vista Service Pack 1 (SP1) (x86-based and x64-based editions)
•Windows XP Service Pack 3 (SP3) (x86-based editions)
•Windows XP Service Pack 2 (SP2) (x86-based and x64-based editions)
2. After migrating the physical server to virtual, the server would not start unless the Domain Controller of which the host Hyper-V server was a member of was running. Because I did this in a lab environment, I first installed Server 2008 and Hyper-V in a workgroup. Then I created a virtual server to use as a domain controller. I made the Hyper-V host server a member of the domain. Then I created a second virtual server to be the SCVMM server. The SCVMM server needs to be in the AD domain. Using the second server I did the P2V to create a 3rd virtual machine on the host. The P2V’d server is not in a domain, just a workgroup.
a. After shutting down all 3 virtual machines and then rebooting the Hyper-V host, the virtual P2V’d server would not start. Hyper-V manager could not even connect to the vm to get the properties, etc.
b. Starting the SCVMM server did not help. SCVMM on the management server could not connect to the P2V server either.
c. Only after starting the DC did Hyper-V manager (on the host) and SCVMM (on the management server) both see the P2V converted server. After that, the P2V’d server started fine.
d. I confirmed this several times by shutting down all the servers and selectively starting and testing the various vms. The dependency seems to be consistent and only on the DC, not SCVMM.
3. This should not affect production systems as there should always be a domain controller available.
Hi Bjorn and Serverrat, thanks for your replies!
In September I will be visiting VMWorld in Las Vegas and the CPU type is certainly one of the things I will be asking at the Microsoft stand. I will keep you posted.
And Serverrat is right about the intergration services. I also stumbled upon the Microsoft site with supported Guest Operating Systems. After I upgraded my Vista virtual machine to SP1 I still wasn’t able to press the “install intergration services” link, as it was greyed out.
But when I mount the intergration services ISO file manually it installs perfectly! And I actually able to use my mouse when I connect to the virtual machine from SCVMM! Well I can move my mouse, the buttons still aren’t working….
Hi, first of all Thanks for the article!
Is there any new information already regarding the CPU type?
I\’m really looking forward as i\\\’m stuck on finding other (good) resources (also at microsoft) describing this
Hi, first of all Thanks for the article!
Is there any new information already regarding the CPU type?
I’m really looking forward as i’m stuck on finding other (good) resources (also at microsoft) describing this
Hello,
I\’m also interested how SCVMM CPU type is related to Hyper-V Manager CPU resource allocation. Have you figured this out?
Thanks