Here is the issue... We are in the process of upgrading our hosts to 4.0. In our lab environment, while testing this I noticed that (while in vcenter 4 and between 4i hosts) I could not VMotion a guest between hosts while it was powered on. It gave an error reading:
Host cpu is incompatible with the virtual machine's requirements at CPUID level 0x1 register 'ecx'
I am a novice at this stuff still and was unsure why as these hosts all worked together well while running 3.5 update 4. I called and opened a case with support. They of course figured it out quickly. I am however not thrilled with their solution:
Shut down the guest, clear out the filed in CPUID Level 1 "ecx"
A previous patch to 3.5 implemented this ID to be entered into the filed: "R
- -R --R- -R-0 ---- ---- -H -R"
Once the field is cleared, power the guest back on and it can be VMotioned between any compatible host.
This means there will be 3 down times for a guest during the 3.5 to 4.0 migration. (Tools upgrade, Hardware upgrade, and now the fix to the CPUID).
I am asking if anyone knows of a way to script this so it does not have to be powered down to clear this field in CPUID. If you have any suggestions I would greatly appreciate it. We have 600 guests to move in the next few weeks and would hate to have to manually do this for all of them.
Thanks in advance