On Tue, 22 Jan 2019 at 18:51, Sean McGinnis <sean.mcginnis@gmx.com> wrote:
On Tue, Jan 22, 2019 at 07:04:05PM +0100, Ignazio Cassano wrote:
Hi All, Please, I' d like to know if cinder backup and/or cinder snapshot call qemu guest agent for fsfreezing. If Yes, does it freeze file systems in the volume? Regards Ignazio
Unfortunately no, initiating a snapshot or backup from Cinder does not call out to Nova to do any guest quiescing. There would need to be something else coordinating the calls between the guest OS and initiating the Cinder snapshot to do that.
Although it wouldn't help making a consistent snapshot of an instance with multiple disks, for a single disk it shouldn't matter if the guest is quiesced as long as the backend can make an instantaneous snapshot. I'm pretty sure many (most?) backends would support that; certainly plain old LVM does. Does cinder use this functionality where it's available, and would that solve the problem you're trying to address? Matt
Sean
-- Matthew Booth Red Hat OpenStack Engineer, Compute DFG Phone: +442070094448 (UK)