Single template for single and dual processor VM's

[ablej]

Does anyone have recommendation on using a single template for single and dual processor VM's. I remember in the past that you shouldn't change the number of processors on a VM is this still the case.

If you find this information useful, please award points for "correct" or "helpful"

[khughes]

Depending on which one you go with, the HAL will be different between a single processor and a dual processor. If you're ok with having a 1 vCPU template then after you deploy adding a second vCPU and changing the HAL I don't see that big of an issue. I'm sure it would be cleaner if you installed the OS with the correct amount of vCPUs assigned.

• Kyle

[dkfbp]

Hi,

We always create our templates with single processors. If needed we then change the particular vm to smp afterwards.

Best regards

Frank Brix Pedersen

[paulo_meireles]

I assume you're talking about Windows 2003 Server VMs. Before SP2, a machine (VM or physical) couldn't be reverted to Uniprocessor Kernel after being upgraded to Multiprocessor Kernel. SP2 solves this.

We have Uniprocessor templates and we always deploy machines as Uniprocessor.

When we need to, we just additional processors to the VM; upon bootup, the additional processors are detected, the multiprocessor HAL/Kernel is installed, it reboots again and all is well.

If we ever need to, we remove the additional CPUs and power up the machine; however, we now have to revert to Uniprocessor manually (through the device manager) as it doesn't do it automatically.

This cycle can be repeated as many times as you wish.

Paulo Meireles

[Troy_Clavell]

I agree, a single vCPU for a template is the way to go. Once deployed if needed change to a 2vCPU VM. I don't believe you have to make any HAL adjustments within the VM when going from single to dual. Just power off the VM, change to 2vCPU's and reboot. The HAL should adjust correctly

[RParker]

Before SP2, a machine (VM or physical) couldn't be reverted to Uniprocessor Kernel after being upgraded to Multiprocessor Kernel. SP2 solves this.

That's not true. The ability to change to Uniprocessor has been there since Windows 2000/XP. It required a repair of windows, but it can easily be done. So it's not related to only SP2.

[paulo_meireles]

Thank you for the correction. You're half right: it's true that it's "possible", but it's not true that it requires a repair. There are other ways, namely using devcon or upgrading manually and later performing a driver rollback. However, you will certainly agree that doing a repair, using devcon or doing a driver rollback are a royal pain compared to simply selecting the correct HAL/Kernel in device manager... and that's only possible since SP2.

Here's an old thread about this: http://communities.vmware.com/thread/29202

Paulo Meireles

[RParker]

However, you will certainly agree that doing a repair, using devcon or doing a driver rollback are a royal pain compared to simply selecting the correct HAL/Kernel in device manager

Not really. According to this kb from Microsoft (which is what I have been using for years) the 'official' way to do it is just that, a repair. And it's as simple as put your CD in the drive, install as if you were doing a NEW install (you skip past the first screen for repair) and move on to where it will ask for location of install, at that point (assuming you have the correct version as the same one you want to repair SP1 -> SP1, Windows 2003 -> Windows 2003, etc..) then all you have to do is let it come up, Press F5 (instead of F6 for OEM drivers) choose the HAL, and that's it. You wait. It updates the executables, and you have to run SP update again, but it it doesn't lose any programs or settings.

A repair takes the same time as a NEW install, but it's not that difficult. Yes it is a pain to do it because of the time and slight aggravation, but even with Windows 2003 SP1 a rollback sometimes wouldn't work, but a repair will 100%. The trick is making sure that you have the right version of Windows because if you install Windows XP SP2 and then try to do a repair an Original Windows XP CD (pre-SP) will not work, it must be the same one as the one used to install, and then if you install SP3 later, you may think you installed Windows XP SP3, but when the repair doesn't recognize the version of Windows that's when you have to try a different CD, so between Windows XP, SP1, SP2, SP3, and Windows 2003 SP1 SP2, and Windows 2003 R2 SP1, SP2.. that's quite a few combination's to keep up with, and we have ALL of these in operation.

So normally yes a rollback would work, but if it doesn't a repair most certainly will, and sometimes that's the only way to go back to UniProcessor.

But as you already stated, keeping 1 template as your central install and changing the CPU later and letting Windows use Plug N' Pray.. that's all that is needed, no need to keep 2 or 3

different versions of Windows just for different HAL's.

selecting the correct HAL/Kernel in device manager... and that's only possible since SP2.

Well technically correct for Windows 2003, but this DID exist in Windows 2000 as well, you can flip flop much easier in Windows 2000, it's much more forgiving for HAL changes from the hardware device manager, so SP2 true for Windows 2003, but this ability to change HAL existed before Windows 2003 also.

[paulo_meireles]

The article you mention is about XP; I was specifically addressing Windows Server 2003.

The question was about "things having changed lately"; I pointed a change: Windows Server 2003 SP2 allowing to pick Uniprocessor or Multiprocessor kernel at will on the Device Manager.

I'm glad we at least agree on having a single template.

Paulo Meireles

[RParker]

The article you mention is about XP; I was specifically addressing Windows Server 2003.

Yes I know the article is about XP, but it applies to ALL versions of Windows. I couldn't find the one that includes specifically Windows 2000, 2003 but it still applies.

The question was about "things having changed lately"

And things didn't really change, because Windows 2003 SP1 DOES let you rollback.. it's just flaky, they 'broke' something, because Windows 2000 did it fine. So the poster is probably referring to the fact that this did in fact work without fail at one point in time, hence Windows XP/2000. So the things didn't change, they were temporarily unable to complete the request , please try again later (a la SP2). But I know with SP1 it did work, because the majority of the VM's we use are still Windows 2003 SP1, and I have done a few of those back to Uniprocessor.