On Wednesday 29 October 2014 13:29:25 Eric Blake wrote:
On 10/29/2014 01:07 PM, Thomas Stein wrote:
About the --quiesce option. Do i need to do something inside the vm? The most commonly would probably be a sql server running inside the vm. Do i need to tell the sql server something about the --quiesce option i use? I read this article here which suggests such a procedure. Okay, it's vmware, but... Is that right?
For --quiesce to work, you have to have qemu-guest-agent installed and running in your guest, and also inform libvirt via the domain XML to establish a channel to the guest agent. Furthermore, if you want your sql database to be at a stable point, you can install freeze hooks in your guest that get invoked prior to freezing the file system and just after thawing it (that is, qemu-guest-agent already has documented hooks that let you do any additional prep work beyond just freezing the file system).
A quick google search found this: http://callecalle.uach.cl/ovirt-engine/docs/manual/en_US/html/Technical_Guid e/QEMU_Guest_Agent_Overview.html
Sadly, it didn't spell out the name of where you install hook scripts into the guest. But this commit is pretty telling: https://github.com/qemu/qemu/blob/master/scripts/qemu-guest-agent/fsfreeze-h ook
Thank you very much Eric. The hole thing now raises a few more questions. But maybe i will ask them later. :-) cheers t.