Error enabling EVC on identical hardware

[dnetz]

Hi,

I was under the impression that if you wanted to enable EVC, you could create a new cluster with EVC, move one host in and then vmotion between the two to avoid downtime. However when I try to vMotion between two identical hosts (HP DL360 G5, 2x3Ghz X5450) running ESX 3.5U3 and ESXi 3.5U3 respectively from the old cluster to the new one, I get the error below, indicating that SSE4.1 has been disabled by EVC. Is EVC working as intended here? I'd rather not edit any masks manually as suggested in the KB1993 article and it's just a lab environment so it's just for my future reference.

Thanks in advance,

Daniel

[JonRoderick]

Can you confirm Execute Disable Bit is enabled in the BIOS on both hosts?

Jon

[dnetz]

Yes, otherwise vCenter wouldn't have shown the hosts as EVC-compatible, right?

[Texiwill]

Hello,

THat is correct. Sounds like you may have something else going on. There are several other BIOS settings in the hosts that will affect vMotion you may want to look at the Processor settings screens of the BIOS side by side.

Best regards,
Edward L. Haletky
VMware Communities User Moderator, VMware vExpert 2009
====
Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.
Blue Gears and SearchVMware Pro Blogs -- Top Virtualization Security Links -- Virtualization Security Round Table Podcast

[dnetz]

I've reset BIOS on both hosts now, checked the version and made the same changes on both hosts, I'm still getting this error. This time I tried to migrate from ESXi to ESX instead of the other way around but it doesn't seem to matter. Any other ideas?

[Texiwill]

Hello,

If you can join them to an EVC enabled cluster then things should work.... However, you may have a specific issue that was not addressed by EVC, I would open a Support case with your VMware Support Representative over this.

Is it just 1 VM that has this issue or all of them?

Best regards,
Edward L. Haletky
VMware Communities User Moderator, VMware vExpert 2009
====
Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.
Blue Gears and SearchVMware Pro Blogs -- Top Virtualization Security Links -- Virtualization Security Round Table Podcast

[kjb007]

This sounds correct. Since the vm started on the non-EVC cluster, the SSE instructions were available to the vm. Now, most likely, the vm, if it's a server, is not using those instructions, but moving that vm to the EVC cluster would yank those features out of the running vm. This could cause the vm instability problems, so you're getting a warning. If the vm had been started on a server without those added instructions in the CPU, then you wouldn't be seeing the issue.

-KjB

VMware vExpert

[prashantprahlad · Accepted solution]

You could do this only if your VM's features match the EVC baseline. In this case, I suspect the VM is powered on on X5450 and is using the SSE4.1 feature. EVC in ESX 3.5 U2/3/4 will supress the SSE4.1 feature for the EVC baseline. Therefore, you're VM can't get in.

The EVC baseline used in ESX 3.5U2/3/4 corresponds to the Merom, or 'Intel Core 2' baseline. So, in reality, you're trying to VMotion from a Penryn (x54xx) machine to a Merom. That certainly can't be allowed.

[dnetz]

That makes sense, on our new production clusters I'll be running EVC from the start so it's not really a problem. Thanks for the answer!