I've been using Citrx Xenserver for awhile on a few machines that don't support Hardware Virtualization as a test for various small servers.

I recently have been experimenting with moving the PV Vms between machines but Xenserver gives me errors that roughly say I need to have homogenous hardware for this to work.

Because of this I haven't been able to setup XenMotion or any of the nice features that come with server pooling in Xenserver.

I'm considering moving away from XenServer, however I can't seem to find a Hypervisor that explicitly supports non-homogenous clusters.

On a side note, we do have a few idenitally configured Dell 1950s that haven't had any VM solution setup on yet, so if we can find a solution that can allow us to move PVs to those as well that would be great. Non free solutions are OK as well.

What hypervisor will allow this? Thanks!


You'll need homogenous hardware (CPUs mainly) if you want to do live migration. You don't mention if it's OK to shut the VM down to do the migration or not, but I'm assuming you want to do it while the VM is still powered on.

If that's the case, then as far as I know, there's no hypervisors that support live migration to non-homogenous custers because it simply isn't possible. Differences in CPU architecture mean that the VM and its guest OS are operating in certain manners that are impossible on different architectures. Even a single CPU generation mismatch can be enough to make this impossible.

  • This is correct, although there's a possible workaround that may fit the OP's scenario - Hypervisors expose the underlying CPU instruction set and features to guest VMs - So migrating them to dissimilar CPUs without powering them down just doesn't work. The only feasible workaround is to 'mask off' CPU features that differ between 'similar' CPUs. This is something that VMWare vSphere supports with it's CPU Masking feature. – Chris Thorpe Nov 23 '10 at 23:28

I patently disagree with the other answers. Last year (2009) Intel announced their VT technology that specifically allows for VMs to be migrated live between similar, but not exact CPU types. As expected, this only works with the Intel Xeon line of processors as shown on the FlexMigration home page. I don't know of a similar offering from AMD.

To find out if a particular hypervisor supports this, I believe that you will need to see that it supports the Xeon VT-x line of processors. If you aren't sure, ask a sales rep and they will gladly help you get to the bottom of this. VMWare's product line was supported on day 1 after the announcement.

Here is a detailed white paper: http://download.intel.com/it/pdf/Testing_Live_Migration_with_FlexMigration.pdf

Note: I have absolutely no business or personal relationship with Intel - I was just paying attention when they announced it.

  • in that case, all CPUs that contain that architecture would be considered homogenous (although that's not the dictionary definition of the word). You're still not going to be able to do a live migration from Xeon to Opteron, for example. – Mark Henderson Nov 24 '10 at 2:33
  • In the initial days of virtualization, including those that the author is still living in, homogenous CPUs mean the exact CPU family all the way down to the exact stepping. Purchasing is an absolute bear. Intel made that problem a little easier. If you want heterogenous to include different CPU manufacturers, then you are correct in saying that we aren't there yet. What Intel lets us do though is buy something pretty close or even newer and adding it to the cluster. – zerolagtime Nov 24 '10 at 3:26

KVM can do this. See http://www.linux-kvm.org/page/Migration or a Red Hat demo video from 2008 at http://www.youtube.com/watch?v=EuhU6jJjpAQ . (The video seems to use Qumranet's ms-windows-based management interface, but it's KVM underneath.) But of course that's going to require hardware that supports virtualization.


You can also check PlateSpin/Novell solution. If I remember it correctly it is called Platespin Migrate or something. It is rather expensive but it allows live migration even between hypervisors (for example between VmWare and XenServer).

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