ESX 5.5 with enterprise plus license but can not add more than 32 vcpu per vm

Question

I have 40 available logical processors but can not allow vms to have more than 32 vcpus? what is wrong? how to fix this?

you're probably doing something wrong if you are trying to assign 80% of available cores to a single vm. Perhaps you would be better suited to run this machine on bare metal? — SnakeDoc, Dec 08 '15 at 18:41
There is a reddit thread about this now! But the reason why you would do this is SAP HANA, and often you will see a single VM per host with all resources allocated to it. You do it to make management easier, and the performance impact is minor. — Rqomey, Dec 09 '15 at 12:22

score 8 · Answer 1 · edited Apr 13 '17 at 12:14

8

Make sure you're using the vSphere Web Client to do this and have updated VM hardware versions...

But I should warn you... Making a virtual machine with more than 32 vCPU is probably a bad idea. Especially on a host with 40 cores.

Can you provide some detail on what you're trying to do and why the VM requires so many resources?

edited Apr 13 '17 at 12:14

Community

1

answered Dec 08 '15 at 13:39

ewwhite

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score 0 · Answer 2 · answered Dec 08 '15 at 12:36

As of this Document: https://www.vmware.com/pdf/vsphere5/r55/vsphere-55-configuration-maximums.pdf the max number of vcpu per vm is 64.

But remember, you can only assign 64 vCPUs if you have 64 physical cores in your machine (or 32 cores with hyper threading). You can read about the limitations here: http://pubs.vmware.com/vsphere-55/index.jsp#com.vmware.vsphere.vm_admin.doc/GUID-13AD347E-3B77-4A67-B3F4-4AC2230E4509.html

It then even depends on the Operation System you are using. To give you better feedback we need to know which physical CPU you are using, how many Sockets do you have and then which OS you are using for the guest.

score 0 · Answer 3 · answered Dec 08 '15 at 15:09

I'm having trouble finding a single authoritative source for this, but in short, you need to be at virtual hardware level 9 (vmx-9) or later to use more than 32 vCPUs.

ESXi version   VMX version   Max vCPUs
     5.0             8           32
     5.1             9           64
     5.5            10           64
     6.0            11          128

Newer versions of ESXi can use older VMX versions, so just because you're on ESXi 5.5, it doesn't mean that all of your VMs are necessarily at VMX version 10. You can upgrade the VMX version of a VM, though only to the latest version supported by your ESXi host; ESXi won't let you choose to upgrade to an intermediate version. Note that upgrading the VMX version can't be done on a running VM, so you will need to take an outage to do it.

Meanwhile, you _know_ something is wrong about this request... — ewwhite, Dec 08 '15 at 15:38
True, for most workloads, that many vCPUs is more likely to hurt performance than it is to help it. — James Sneeringer, Dec 08 '15 at 17:23

ESX 5.5 with enterprise plus license but can not add more than 32 vcpu per vm

3 Answers3