Open Stack

2012/10/29 Steve Anderson <dafridgie at gmail.com>:
> Hi All,
> I've been testing snapshotting in the lab and have found that i get
> interruptions to service when taking snapshots of the VM. I notice that
> depending on Vm size, this interruption lasts longer the bigger a Vm gets.
> I'm using Openstack Folsom on 12.04 but also see this with essex as well.
>
> I am aware that this isnt snapshotting in the sense that it is a 'point in
> time snapshot of the Vm disk and memory contents' as is the case with other
> hypervisors using their management toolsets.
> Openstack snapshotting creates a crash consistent copy of the virtual
> machine as a snapshot - essentially a Vm clone
>
> So my questions are:
> Is there anyway that i can reduce the 'pause time' experienced by a Vm
> during snapshotting that anyone is aware of ?Any known workarounds etc... ?
> Also, are there any plans for introducing full memory+ disk snapshot
> capability into Openstack for KVM at some point in the future? (Qemu/libvirt
> do seem to support this outside of Nova/Openstack if I'm not mistaken).
> In our environment , true snapshot capability for VMs would really clear
> away a big hurdle for better customer adoption
>
> Any help or guidance would be really appreciated
>
> thanks for your time
>
> Steve A
>
>
>
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>

Instance is actually suspended during snapshot (but not during
snapshot uploading) and i don't know any workarounds that could
significally reduce this delay.
However, you may keep your root VM filesystem small enough and use
volumes for extended storage (see
http://docs.openstack.org/trunk/openstack-compute/admin/content/ch_volumes.html).
Also, there was a bluperint for live snapshotting:
https://blueprints.launchpad.net/nova/+spec/live-snapshots