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Does ESXi 4.1 really limit the number of processor cores used on the host?

gateguard
gateguard asked
on
I have this:

Product: vSphere 4 Hypervisor Licensed for 2 physical CPUs (1-6 cores per CPU)

My question is this:

If each of my VMs only has 1 virtual processor allocated (in a few cases 2 virtual processors) is the host machine (running ESXi 4.1) really only using a maximum of 12 cores, even though I have 2 AMD 8-core processors installed.

The host does see all those processors, as evident from the Summary page:

CPU Usage: xxxx Mhz, Capacity 16 X 1.999 GHz

Is there a way to monitor the processor cores to see if there are really 4 cores that are never being used.  (VMWare says they are never being used... but I wonder.)

Thanks.
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Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017

Commented:
If you have a license for (1-6 cores per CPU), it will only use the first 6 cores of the CPU, unless you upgrade to Enterprise Plus.

Edit the vCPU settings, Affinity, and you should be able to "see" the cores you can run the vCPU on.

try esxtop in cpu mode
Commented:
A standard license will as Hanc has mentioned give you 6 cores. A plus license will let you see upto 12 cores.
You can of course assign 2 standard licenses to each socket to see upto 12 cores..
Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017

Commented:
also if you have the time, you can experiement with

cpuid.coresPerSocket

http://www.yellow-bricks.com/2009/06/04/per-processor-licenses-for-your-application/

and, you can use coreinfo in the VM

http://technet.microsoft.com/en-us/sysinternals/cc835722

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Commented:
markzz, I tried to add a second license but it just replaced it, it didn't add it.
VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017
Commented:
You will need to add an Enterprise Plud license to use 12 Cores.

If you upgrade your licenses for ESXi 5.0 there are no Cores limit anymore with vSphere 5.0.
Top Expert 2010
Commented:
I have dual socket, 12-core hosts and had the same question you did several mos ago. Yes, you can use a lower-level license, but no, you won't be able to use the extra available cores unless you have Ent+ licensing. Can you believe that both VMware support AND VMware licensing folks didn't really know what would happen if I used a lower level (just Ent) license???!! Silly people! Anyway, on the Summary, you will see all the cores the host has, but won't be able to use them all (only 6 per host).

vSphere 5 does indeed mitigate that limitation, but then again, it introduces RAM limitations.

Regards,
~coolsport00