Change from Multi cpu to single cpu on Windows Server 2008 R2 64bit VM - works...any issues?

[macgreen]

I must have missed the notice when this was possible.

I decided to change a Windows Server 2008 R2 64bit Standard Edition guest OS (running the "ACPI x-64 based PC" HAL) on Virtual hardware 7 (ESX4.1 hypervisor) from 2 vcpu to 1 vcpu.

It just works. I did not do any fancy footwork with the device manager or driver prior to just shutting down and making the change in VM settings.

Guest OS boots and works. But I am still apprehensive as if there is something going to cave in or happen later on. As obviously in the past this required some extra work.

Should I be concerned? As will be deploying vms from this as a template.

[vmroyale]

Hello.

In this TechNet article by Mark Russinovich, he explains the changes in 2008. One of the quotes:

"One  of the low-level changes to the system is that Windows Server 2008 only  includes a version of the kernel designed to work on multiprocessor  systems. In the past, Windows used a version specific to uniprocessors  on machines with a single CPU because that version could achieve  slightly better performance by omitting the synchronization code  required only in multiprocessor environments. As hardware has become  faster, the performance benefit of the optimizations has become  negligible, and most server systems today include more than one  processor, making a uniprocessor version unnecessary."

So, you don't need to worry about this any longer in Windows 2008!

Good Luck!

[sssstew]

yep, agreed with above.  The change is easy and have completed many times myself, all without issue.  Note if you use the enterprise edition of windows you can hot add CPU, but cannot hot remove yet.