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
On Mon, Oct 12, 2009 at 5:48 AM, Dennis J. 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?
Grant McWilliams
Some people, when confronted with a problem, think "I know, I'll use Windows." Now they have two problems.
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, DennisCan'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
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, DennisCan'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
Gack. I added an additional Raid1 pair to my machine just before I planned to bring it over to the office and I did something dumb and locked out.
I have the pv's, vg's and lv's cleared. All I need to do is get on root and remove a line from fstab, but I can't get it out of read only mode to save the edit.
My root login at "Repair Filesystem" seems unable to make the file writeable. I have done this in past with Knoppix, but can't seem to file the utility to make the write editable (same with CentOS and other live CD's, am downloading newer BackTrack now).
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Ben M. -
Dennis J. -
Grant McWilliams