Quad Core not recognized in ESXi

[mattmcdermott]

I have built a whitebox ESXi 4 machine. It is really working fine, but it is not reporting 4 CPU Cores on a Q9400 Intell Processor. The processor is new and it worked fine when I put Windows Server 2008 on it, but in ESXi it only reports 1 CPU Core and only 1 core per socket and 1 logical processor. I am not for sure what could be causing this, unless this is a Bios issue with my motherboard. Fairly inexperienced ESXi guy so I understand I may be doing something incorrectly on the setup.

Motherboard is a Asus PQ5L-E running Bios 1005

Trying to attach picture, but getting errors starting the image tool. WIll try to add later.

Any help would be appreciated

thanks

mattmcdermott

[fritzdimmel]

Hi,

I'm having the same problem.

I've the same Intel Q9400 Core2Quad processor (4x2.66GHz) and ESXi4 does only recognize one.

On the Alt+F11 console I get the following error:

TSC: 2109285808 cpu0:0)SMP: 496: Invalid HT config (numHT 4, numPCPUS 4)

Can anybody help?

I've ESXi 4.0.0 build-164009

Thanks a lot,

Fritz

[wayneoakley99]

no answer but i seem to recall during the announcement that there was some limitation on the number of supported processors and cores per processor with the free version.

i have been trying to find some documentation stating any limitations on the free edition but have not found anything so far. a limit of 1 processor 1 core does not seem correct so it is likely something else.

wayne

[fritzdimmel]

Hi,

thanks for your reply.

Soon after writing, I found another thread (http://communities.vmware.com/message/1200365)

This helped. I had to set MAX CPUID in BIOS to disabled. Now ESXi4 sees all cores and runs fine.

Bye,

Fritz

[darkfriend]

It took me along time to figure that out too...and write that thread.

[xgrep]

Hi all,

I just installed ESXi 4.1 on an HP server with a Xeox 5450 quad-core CPU. The host sees all four cores fine, and is happy to allocate them to a single VM running Vista Enterprise 32-bit, but the Vista VM only sees two CPUs. The BIOS on the real machine is set to allow all four cores, and there's no BIOS setting in the Phoenix BIOS on the VM that has anything to do with cores or CPUs (at least I didn't see any).

Why does the Vista VM only think it has 2 CPUs? If I install it native on the system, it sees them fine. I've been all over the internet looking for an explanation, but am totally stumped.

Thanks in advance for any clues!

[DSTAVERT]

I would limit the use of multi CPU virtual machines. Start off with a single vCPU and add as necessary based on the actual needs of the guest.

Windows desktop OSs are limited to 2 CPUs. Running in a virtual environment your cores equate to vCPUs

For future questions you would be wise to create a fresh post for your problem.

[xgrep]

Thank you for that light-bulb moment!

In all of the discussions I read, it never dawned on me until your answer that Windows does not treat cores and CPUs identically. So while ESXi sees the four cores, it presents them to the VM as four CPUs. Vista can handle the single quad-core CPU of the real system, but not the four vCPUs of the VM.

On the point of utilization, I can now see that Vista (or any OS) might run better on a single vCPU in a hypervisor running on a multi-processor system (cores or CPUs) if the hypervisor can make better use of the resources than the guest OS would. When I worked with IBM's VM/370 in the mid-'70s, we did find that to be the case: the hypervisor could distribute load more efficiently across resources than OS/360 or MVS. So it was often the case that either of these had better overall throughput in a VM than running native (depending on workload, etc.).

I'll do some comparisons of a 2 vCPU VM vs a single vCPU in my environment to see which is better. It will of course depend on how well ESXi distributes demand for resources.

Thanks again for the explanation. I won't need to be asking any further questions on this subject.

[DSTAVERT]

An old old hand at virtualization. I haven't seen reference to the 360 or 370 for a long time.

Since it is so easy to start small and add resources as necessary it is the best place to start.