Re: [CentOS-virt] Xen to KVM migration

On Mon, Oct 12, 2009 at 10:30 AM, Dennis J. dennisml@conversis.de wrote:

On 10/12/2009 06:17 PM, Grant McWilliams wrote:

...

On Mon, Oct 12, 2009 at 5:48 AM, Dennis J. <dennisml@conversis.de mailto:dennisml@conversis.de> wrote:

Hi,
I'm thinking about how to go about migrating our Xen VMs to KVM.
Migrating
the configuraton should be easy using the virsh dumpxml/define
commands but
what is the best way to transfer the (logical volume based) images
without
too much downtime for the guest system?

Can rsync operate on logical volumes? If so I could potentially use
"dd" to
transfer an initial copy of the image to the destination host and
then shut
down the guest, rsync the logical volumes which shouldn't take too
long as
not much data has to be transfered thanks to the initial "dd" and
then boot
the guest on the new machine.

Is something like this possible or would you do something different?

Regards,
   Dennis

Can't you just use the LV in place with KVM?

I may be wrong about this but isn't running KVM on top of the Xen hypervisor a problem? Maybe this has changed but I thought in order to be able to use KVM you first have to disable the Xen hypervisor and boot into the regular Kernel.

Regards, Dennis

But once you have your XEN DomU config file converted to KVM you could in effect just reboot the Dom0 into a standard kernel and use KVM.

Unless of course you're only moving one DomU to KVM then it wouldn't work.

Grant McWilliams