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When using KVM for virtualisation on Redhat (RHEV), is it possible to live migrate VMs between AMD and Intel boxes? In particular, I'm interested in Opteron 6100 and Intel Xeon 5200 series.

There was an AMD demo in 2008, but I can't find out whether it's now available now or not. On this Red Hat docs page I see no requirement for the same CPU.

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No, you cannot migrate between different CPU vendors. with RHEV, you should not be able to place an Intel and AMD hosts in the same cluster (migration domain)

No virtualization platform allows cross vendor migrations today, normally you get blocked during the setup stage, so you don't get crashed VMs.

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  • I can confirm this is the case with RHEV. I believe they have CPU baselining planned in the future since it's technically possible to do with KVM, but right now you can't add a cluster of mixed hosts. There are issues with different TSC implementations, processor feature sets, etc which I believe they're still working on.
    – Beerey
    Feb 17, 2011 at 2:04
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KVM lets you specify the kind of CPU 'exposed' to the VM by choosing the specific subset of features it announces to the BIOS. If you use -cpu host, it simply exposes the same features as the host; but there are other more 'generic' subsets, like -cpu qemu64. If you use the same on different machines, you can freely migrate between them.

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  • have you ever tried migrating amd>intel and vice versa?
    – dyasny
    Jan 25, 2011 at 13:58
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    sure; the trick is to expose only a common subset of features. that's the whole idea of -cpu quemu64 see the FAQ: Does KVM support live migration from an AMD host to an Intel host and back?
    – Javier
    Jan 25, 2011 at 15:51
  • Well, this will not work in RHEV
    – dyasny
    Jan 26, 2011 at 11:33
  • @Javier Is there any performance overhead to use -cpu qemu64?
    – Oleg Neumyvakin
    Sep 5, 2020 at 10:24
  • not exactly "overhead", but applications won't use any modern facilities, vector registers, or hashing instructions, or things like that. I haven't used that in a looong time, so it's very likely many applications won't start because they need SSE or MMX.
    – Javier
    Sep 6, 2020 at 16:25
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I think migration should work OK as long as you are using 64-bit (and otherwise identically set up) distributions in both boxes. But if the other box runs some other version of RHEV or has 32-bit version installed, then there are problems waiting for you.

(Both boxes running a 32-bit distribution should work OK, too. It's only if you mix up 32 and 64 bits, then there are problems)

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I dont thing so it will migration done in AMD and Intel box it has identically same architect, it will show you its migrating but it will zombi status. And both box has to be RHEV version

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If you use a HVM based virtual environment then yes. Your CPU's must support Virtual Hardware requirements. If you look at KVM documentation you can do it - and those CPU's do support it.

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Yes, you can live migrate across platforms. I'm currently experimenting with this using KVM in Arch Linux. It works

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