Issue with Windows 2003 VM after adding additional vCPU

[jmedd]

ESX 3.5 U1

Had a Windows 2003 SP1 VM which needed to have an additional vCPU added to take it to two vCPU (yes I know it may not necessarily improve the performance, but it was the customer's decision :smileyblush: ). Anyway since I had done serveral of these in the past for another project, I powered down the VM, added the additional vCPU and powered it back up. It booted as far 'Applying Settings' and would then reset itself, boot to the same point and continue in a loop.

So I powered the VM off, removed the additional vCPU, powered it back on and it did the same thing. The only way I could get it to boot was to use 'Last Known Good Configuration' and it then complete boots into Windows. Unfortunately at each reboot now the same reset halfway through exists and then only way to successfully boot is with the 'Last Known Good Configuration' each time.

My mind is to now build a clean VM with 2 x vCPU's and reinstall the application which is on the troublesome box, but I thought I'd post here in case someone had a better idea of going forward or knows if there are any known issues with adding an additional vCPU with ESX 3.5 U1 and Windows 2003 Standard SP1?

Thanks

[Texiwill]

Hello,

Moved to Virtual Machine and Guest OS forum.

You may have to update the HAL to get things to work properly. Other than that there are no issues. You could instead revert back to one vCPU and then use VMware Converter on the VM to do a V2V and increase the # of vCPUs, it will update the HAL appropriately.

Best regards,
Edward L. Haletky
VMware Communities User Moderator, VMware vExpert 2009, DABCC Analyst
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[jmedd]

Thanks for the info. The strange thing is it has already updated to the Multiprocessor HAL; I will check out your suggestion anyway though.

Thanks

[AlbertWT]

Thanks Edward, now I learn that by using vCenter 4.0 Stand alone i could modify the existing VM hardware safely wather than making abrupt changes directly from the properties.

I also found it quite useful that vCenter is also capable of creating a cloned VM from a template provided that clone is SYSPREPed.

Kind Regards,

AWT

[jmedd]

I thought I would post back in case anyone was interested that I eventually resolved this issue. A couple of days after the last reply I took a clone of the troublesome VM so that I could run through some troubleshooting with the clone rather than the live machine. Strangely enough the clone booted up fine without having to go through the 'Last Known Good Configuration' each time. I went back to the original machine and discovered that now booted up without issue too. Looks like Windows sorted itself out somehow over those couple of days, wish I knew how.

Anyway I tested adding the additional vCPU to the clone and since that worked fine I went back to the original, added the extra vCPU and that was fine too.

Thanks

[JohnADCO]

That is good to hear, thanks for posting back....

I read odd things like your post from time to time and I just have to scratch my head, I add and subtract VCPU's all the time from various VM's and gauge the results.

2 Vcpu seems to work as it's supposed to for me, I can immeadiately see in perfmon that multi CPU's are indeed being used. I must admit, I have never tried more than 2 vcpu's as I have not had a VM that seemed to need that.