[Openstack-operators] nova snapshots should dump all RAM to hypervisor disk ?

Antonio Messina antonio.s.messina at gmail.com
Sun Apr 24 10:38:42 UTC 2016


I actually have a card in my trello board to implement live snapshots,
pointing to this link
http://www.sebastien-han.fr/blog/2015/02/09/openstack-perform-consistent-snapshots-with-qemu-guest-agent/

However, I haven't tested it yet. If you test it let me know how it goes.

.a.

On Sun, Apr 24, 2016 at 9:09 AM, Saverio Proto <zioproto at gmail.com> wrote:
>> We are in an even worst situation: we have flavors with 256GB of ram
>> but only 100GB on the local hard disk, which means that we cannot
>> snapshot VMs with this flavor.
>>
>> If there is any way to avoid saving the content of the ram to disk (or
>> maybe there is a way to snapshot the ram to, e.g., ceph), we would be
>> very happy.
>
> Hello Antonio,
>
> I received a new feedback in the Openstack patch review
> (https://review.openstack.org/#/c/295865/) pointing me to this:
>
> https://github.com/openstack/nova/blob/82a684fb1ae1dd1bd49e2a8792a2456b4d3ab037/nova/conf/workarounds.py#L72
>
> so it looks like live snapshots are disabled because of an old buggy
> libvirt. So actually this process of dumping all the RAM to disk is
> not a bad design, but it is a necessary workaround because of libvirt
> not being stable. It makes sense now.
>
> At the moment I am running libvirt version 1.2.12-0ubuntu14.4~cloud0.
> Maybe I can disable the workaround and try to do faster snapshots ?
>
> Any other operator has feedback about this ?
>
> Thank you
>
> Saverio



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