Windows Server 2008 R2 and hot adding CPUs

[jftuga]

I am running a Windows Server 2008 R2 (64-bit) guest OS under the latest version of vSphere 4 / ESXi and want to hot add CPUs.  When I go to edit VM settings, the CPU area is grayed out, so I can't change the number of processors.  What do I need to do in order to make this possible?

Thanks,

-John

[a_p_ · Accepted solution]

If the virtual hardware version is 7 and the OS you configured for the VM support hot add/hot plug you can enable this feature in the VM's settings while the VM is powered off. It's located in the Options tab under "Advanced" -> "Memory/CPU Hotplug"

André