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Is it possible to configure a 4 socket 40 core physical server to be a single VM-Guest using the Virtual Socket and Cores per socket options?

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May I ask why you'd choose to virtualize in this case? – ewwhite Jun 14 '12 at 13:46
I don't see the point in virtualizing indeed. – dyasny Jun 14 '12 at 13:57
JUST KIDDING maybe they accidentally sold operation of a 4 core 40 socket server to a customer :) JUST KIDDING. Another use case would be testing behaviour of software under development on a 40 core system. – rackandboneman Jun 15 '12 at 0:44

What virtualisation solution do you (intend to) use?

Generally, it seems to be considered a bad idea to span VMs across NUMA boundaries (which you get as soon as you assign more cores to a VM than one socket of the physical host offers).

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If you really need all that CPU in a single machine, there's no point virtualizing. The idea behind virtualization is the fact that you have more physical resources than your OS/App can or need to use, so you put them in a VM which is more limited in resources, and then bring up additional VMs, who will share the extra resources the large physical host can provide.

Still, if you really need a beefy VM like that, KVM can support 64 vCPUs, and the number goes higher with every release.

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I believe ESXi 5 allows only 32 vCPUs, other hypervisors probably have similar limits.

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There's very little information in your question. But if you just want to virtualize, perhaps because you want to be able to service the hardware after migrating the VM to another host, or perhaps because you want to be able to back up the entire VM, or because your infrastructure is centered around virtualization, you could do this with Windows Server 2012 and Hyper-V.

The currently released versions of Hyper-V don't support that many cores, but 2012 supports 64 virtual processors and has the ability for a VM to span NUMA nodes. You can play with the beta today, though I wouldn't host production workloads on beta software.

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ability to span NUMA nodes is not uncommon ... but does it iron out the issues with less predictable and worse memory latency? – rackandboneman Jun 15 '12 at 0:46
It does, actually. Hyper-V in Server 2012 will automatically configure the VM in a way that maps nicely onto the underlying hardware, reporting to the guest OS that there are multiple virtual NUMA nodes, each of which is placed in a physical NUMA node. This leads the guest OS to behave well and confine its access (as much as possible) locally within the virtual nodes, which since they are lined up with the physical nodes causes the workload to run well. – Jake Oshins Jun 15 '12 at 5:26

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