cmorris05
Contributor
Contributor

ESX Cluster different number of cores

We currently have 4 servers with two dual core Xeon processors in each. We are looking at adding another server to the cluster and I would like to make the next server have two Quad core processors. Is this possible for the Cluster to have different servers have a different number of processors?

I would assume I could not have any more then 4vProcs on any VM to be able to Vmotion across servers.

Thank you,

Chris

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7 Replies
kjb007
Immortal
Immortal

If you don't have a newer server that has the Intel FlexMigration enabled in the CPU, then you have to be careful mixing CPUs. There are issues with some intel quad cores and dual cores with vmotion. If the new server supports Intel FlexMigration, and you have ESX Upgrade 2 and enable enhanced vmotion, then you will be ok. Otherwise, check the vmotion compatibility from the vendor site. Below are a couple of links, but I'm not sure how recent they are anymore:

-KjB

vExpert/VCP/VCAP vmwise.com / @vmwise -KjB
weinstein5
Immortal
Immortal

The number of cores is virtualized away by the vmkernel so you can mix single core - dual core and quad core and total number of physical cpus - the importnat thing is to make sure the physical cpus are compatible -

4 virtual CPUs is maximum number of virtual cpus you can assign to vm and as long as you have a minimum of 4 cores (you shoulod have at least 8 per best practice) you would be able to vmotion -

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cmorris05
Contributor
Contributor

We have HP DL360 G5s with Xeon 5150 processors. It looks like the only systems with FlexMigration are the newest Quad Core Procs.

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kjb007
Immortal
Immortal

You can go to the HP site, it will have a matrix that shows which Intel processors are compatible for vmotion with others. Without the new feature CPUs, you'll have to manually verify that the new server that you want to add is compatible with the old cpus.

You should be able to match up the processor numbers in the matrix to know for sure.

-KjB

vExpert/VCP/VCAP vmwise.com / @vmwise -KjB
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cmorris05
Contributor
Contributor

I have found the information about the VMotion compatability. The processors we are looking at getting for the new servers are the X5355 Xeon Quad Core. However I was wondering if anyone had an opinion on if it would be better to just upgrade the processors in the existing servers to something like a Xeon X5460 since it uses the newer core and has more L2 Cache. Plus it supports FlexMigration so it should be EVC compatible. Is that going to be important or is it a waste?

Thanks

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kjb007
Immortal
Immortal

If the cost is not prohibitive, I would get the newer processors. That is, if you want to add the new hosts to your existing cluster. Otherwise, this is a moot point. You can get the newer processor as it will be helpful, but not required.

-KjB

vExpert/VCP/VCAP vmwise.com / @vmwise -KjB
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prashantprahlad
Enthusiast
Enthusiast

You need to have at least Merom (Intel Core 2) based Xeons. The more recent Penryn (Intel 45nm Core 2) bases Xeons have the Flex Migration capability. Flex Migration is NOT mandatory for using EVC.

See KB 1003212

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