Mixing CPU types within a vSphere Configuration

[FGLVMware]

I currently have a single ESX 3.5 server which we will shortly upgrade to vSphere 4 U1. This server is physically a HP DL580 G5 with 2 x Quad Core E7330 processors installed.

We plan to add a second vSphere server to the configuration, of similar spec. However, our hardware supplier advises that the DL580 no longer ships with the E7330 processors, and they may well be a different processor installed in the new box. As we intend to use vSphere Advanced on both systems, with vMotion etc. will this difference in processor types present a problem ? I am hearing a lot about this - but cannot locate any concrete evidence stating whether the processors need to be 'identical' in all systems within the 'farm' when using HA features such as vMotion.

Any advice appreciated.

[krowczynski]

Hi,

you can you vmotion also with differnet cpu types, but you have to configure then an EVC Cluster.

Maybe this pic can help you.

Also look here:

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=100321...

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=100576...

MCP, VCP

[BKarciauskas]

I have just finished a similar project.

I had 3x DL380G5 servers with intel x5440 running 3.5. I upgraded them to version 4.0 (along with vcenter etc) and added 2x DL380G6 servers with X5560 procs.

Vmotion between them with the standard configuration is not possible.

I wanted wo implement EVC to fix the vmotion issue however the DL380G5 servers are not compatible with EVC and so this was not an option. My guess is that you might have the same issue

I ended up having to disable the NX/XD flag on each VM to allow the VM's to vmotion between differnet hosts which requires you to power down the VM to make the change.

Also you might want to[take a look at this|http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1993#VC2xESX2x] which shows you how to mask certain CPU features from the VM's.

Cheers,

Ben Karciauskas

Blog - http://karciauskas.wordpress.com

[FGLVMware]

Thanks for the info. These BIOS setting requirements are covered in the KB doc 1003212 which is excellent.

//snip//

Verify the BIOS settings for these processors enable Hardware Virtualization (if available) and Execute Protection. Default BIOS settings may not always enable these features. Hardware Virtualization is Intel VT on Intel processors and AMD-V on (supported) AMD processors. Execute Protection is Intel eXecute Disable (XD) on Intel processors and AMD No eXecute (NX) on AMD processors. Until these CPU features are enabled, ESX hosts with EVC supported CPU types listed below will be unsupported.

//snip//

I take it from your reply that after amending these settings as required in the BIOS of each of your ESX servers, you could then configure the EVC as required and all is well ?

When you say you had to disable the NX/XD flage on each VM do you mean each of your 5 ESX host's or on each 'VM' image residing on those hosts ?

Thanks.

[BKarciauskas]

Thanks for the heads up on the vmware KB. After taking a look at it I think that there is a better way of achiving a similar out come. I am thinking if I am able to get the older hosts to be EVC compatibale that is the preferred option.

In my case I disbale NX/XD flags on the VM's themselves not the hosts.

Cheers,

Ben Karciauskas

Blog - http://karciauskas.wordpress.com

[FGLVMware]

The other KB article earlier in this post (1005764) is also an excellent source of information. Regarding your setup it states:

What is the difference between EVC and the old CPUID masking feature (accessed from the Virtual Machine Settings dialog box, Options tab, CPUID mask option)?

The older masking feature involved applying manual masks to individual virtual machines. EVC takes effect on a whole cluster and all virtual machines in the cluster. More accurately, EVC affects the hosts themselves, making all the hosts in the cluster appear to be the same type of CPU hardware, even if they are different.

Again, thanks for your input.