Am I correct that you can boot up any operating system with either of these virtualization types as they act as a bare metal machine and compile your own kernel?

I am looking to switch over from OpenVZ to a Type-1 (is it?) hypervisor, so more OSes can be booted. I was just wondering if Xen PV, Xen HVM or KVM was a better choice for hosting clients or if it just comes down to personal preference?

I recently bought an E3-1230V3 with 32GB of RAM and maxed it out with a Hardware RAID card for RAID-10 on disks.

So from what I've gathered.

  • XEN HVM = bare metal. like physical machine
  • XEN PV = *nix based and kernel compile
  • KVM = *nix based and kernel compile

Xen HVM is the only type of Xen that will support a different OS. KVM will run anything of course.

As for which to choose, that's offtopic on SF.net


First about differences:

KVM is a kernel based virtual machine. So virtualization becomes a job for the standard kernel of the host. There is no additional hypervisor in between.

XEN is a hypervisor running underneath a ccontrolling VM, called Dom0 (priviledged VM). The hypervisor can run modified, XEN-aware Linux VMs in PV mode. ParaVirtualized VMs have direct, not emulated access to the hypervisor, which can make some operations faster. Fully virtualized VMs use a emulation layer, normally provided by qemu, to access hypervisor resources. You can mix PV and HVM to your liking.

IMO XEN is much more stable than KVM, especilly when running non-linux VMs. But I am a XEN-friend any way.

For personal use I can also recommend Oracle Virtual Box. A user-space virtualization running atop of most common OSes, including Win7, Debian, RedHat.


The latter. For normal workloads there is nothing you can only do with one or another. If you come from OpenVZ I would suggest KVM since it's architecture is more similar to what you know. Xen is a completely different concept.

  • Tim, thanks for your reply. Can you explain or give me some links on how Xen is different over KVM? Thank you very much. – user236402 Aug 6 '14 at 16:12

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