64 bit troubles...

[yougotiger0]

We've been having fits with getting Windows 2998 server R2 to run in our vSphere environment. We keep getting an error when we attempt to install Win 2k8 R2 - incompatible CPU's.

Having done some research, we found that we needed to enable VT in the host's bios. So we made sure all of our hosts had it enabled (and that actually made it so we could use enhanced vmotion...).

We still receive the error when attempting to install Win 2k8. So in my research I found a utility to create a boot CD that you can put in the host and get some information regarding the CPU's and their compatibility with 64-bit. I ran this on one of our hosts and got a message that says:

"VT is not supported on this system due to an inconsistent mix of VT features on different processors."

Also in the log we found that the CPU brand strings indicate:

-intel Xeon cpu e5310.. on bin 1 and

-intel Xeon cpu L5310.. on bin 2

Also, it indcates the following for each bin:

bin1: family: 06 model: of stepping 7

bin2: family: 06 model: of stepping b

We had 3 hosts each with 1 cpu (quad core) and later upgraded them to 2 cpus (quad core). We've had no problems running things (except enhanced vmotion would enable turns out VT wasn't enabled on one host). but we're supposing that something in the stepping of the CPU's is the issue, but all searches for the "VT is not supported on this system..." message have resulted in NO results I'm wondering if anyone can shed some light on this situation for us.

Any help would be greatly appreciated.

[AntonVZhbankov]

So you actually have different CPUs in one server?

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MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[yougotiger0]

We purchased them from Dell to match our servers, and while they are the same model, we're supposing that it's becuase they are different stepping levels.

[AntonVZhbankov]

Make CPUs in the server exactly the same in both sockets.

---

MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[yougotiger0]

Will we run into any issues when we go to vmotion if we swap CPU's around so that they match in the same host, but don't between hosts?

[AntonVZhbankov]

In this case no, even without EVC enabled.

---

MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[yougotiger0]

Just to clarify, we WON'T have any issues even if we DO now have EVC enabled, as long as each host has matching CPUs?

Do you have anything you can point us to regarding the issue so we can do further research?

[AntonVZhbankov]

EVC is used to provide VMotion capability between different CPU families like 53xx and 54xx, and you have only different steppings.

---

MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[admin]

We don't support VT-x on SMP systems where the CPUs report different VMCS revision IDs. In your particular case, Intel goofed in assigning different VMCS revision IDs for the different steppings. Intel has provided OEMs with a microcode update that fixes this issue. The microcode update only works if the BSP is the least capable processor on the system.

Make sure that the lower stepping processor is installed as the BSP, and make sure that you have the latest BIOS update from your OEM. If the BIOS has the microcode update, this should get both processors to report the same VMCS revision ID.

[DSTAVERT]

Just for reference how much stepping difference can ESX(i) tolerate.

[admin]

In most cases, the stepping is irrelevant. However, there are some rare cases where stepping matters, due to some incompatible processor change.

As far as VT-x support goes, the only time that Intel has ever changed VMCS revision IDs across steppings within the same family and model is the case here (Clovertown Bx vs. Clovertown Gx). Intel assures us that this will not happen again.

Even in this case, with the proper microcode update from Intel, the stepping becomes irrelevant.

[yougotiger0]

How do I go about doing a microcode update? Is that the same as doing the Dell Server BIOS update that we can download from Dell, or do we need to do something on Intel's site?

[admin · Accepted solution]

The Intel microcode update should be included as part of the latest BIOS available from Dell.

[yougotiger0]

Bios update seems to have fixed it. THANKS!!