How to P2V Multi-processor Servers to Uni-processor VMs
While troubleshooting poor performing VMs this week I was explaining to a customer the process of trying to downgrade the multi processor HAL of a Windows VM that was created by a P2V migration with VMware Converter. I ended up sending them a link to an older VMware Communities forum thread in which Mike Laverick of RTFM Education provides a quick how to guide. I also wrote (and sent the customer) a post earlier this year that offers similar advice, but P2V multi processor servers to single processor VMs instructs you to install a patch specifically for Windows Server 2003 VMs which then allows you to downgrade to a single processor.
The other difference worth mentioning between these two posts is the links to the Microsoft DevCon tool. Although VMware will not officially support using this tool on VMs, using this utility for forcing a HAL downgrade is possible when all else fails.
Check out the following instructions copied here and the various links in this post for more information.
VMware Communities: VC CPU - 97% and VM OS (Windows 2003) …
I’d back up your VM or make a new one from the template before attempting this. Changing the HAL can cause BSOD as you probably know…
How to downgrade the HAL:
- Right-Click My Computer
- Properties > Hardware Tab > Device Manager
- Expand +Computer
- Right-Click ACPI Multiprocessor
- Choose Update Driver
From here Windows Dialogs vary - but whatever your version - you need to use
- Install from a list or specific location (advanced)
then
- Don’t search. I will choose a driver to install
You should then get the option to change the ACPI type
Some Windows OS (W2K3 if I remember rightly) doesn’t allow a GUI downgrade - but you can force one using MS DevCon utility .. [omitted]
You can the DevCon tool and documentation from here:
o Microsoft Help and Support:
http://support.microsoft.com/default.aspx?scid=kb;en-us;311272
o Microsoft Technet
http://www.microsoft.com/technet/prodtechnol/windowsserver2003/library/TechRef/0f087656-fb2e-4828-9630-e76051a0a608.mspx
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Tags: cpu, microsoft, P2V, virtualization, vmware converter, windows
June 11th, 2008 at 8:16 am
The patch is only required on systems that don’t have SP2 installed, which was released in March 2007.
June 26th, 2008 at 9:47 am
[...] is on a roll with a couple of good articles, one on VMFS storage sizing for performance and one on downgrading the VM HAL after P2V. The title for that second article was “How to P2V Multi-processor servers to Uni-processor [...]