Libvirt/KVM snapshot only in RAW image format

I try to create patch for this bug.
What do you think about that patch ? About test flag ?
I'm not a developer so I prefer to have developer opinion before I prose it to merge.

I think a better solution would be to use the format of the original image.

Ok.
By default, we can use the default original image format and propose flags to customize this.

Nice Vish, I forget to check the flag 'use_cow_images'.
Perhaps adds new tests for other format (vmdk and vdi) ?

Do you think it could be an extension of OSAPI ? When we make a snapshot, the user could choose the image format.
Perhaps an new function call 'export image' ?

Interesting idea. Might be a useful extension for sure.

On Sep 12, 2011, at 12:58 AM, Doude wrote:

> Nice Vish, I forget to check the flag 'use_cow_images'.
> Perhaps adds new tests for other format (vmdk and vdi) ?
>
> Do you think it could be an extension of OSAPI ? When we make a snapshot, the user could choose the image format.
> Perhaps an new function call 'export image' ?
>
> --
> You received this bug notification because you are a member of Nova Bug
> Team, which is subscribed to OpenStack Compute (nova).
> https://bugs.launchpad.net/bugs/824433
>
> Title:
> Libvirt/KVM snapshot only in RAW image format
>
> Status in OpenStack Compute (Nova):
> In Progress
>
> Bug description:
> With the virt driver Libvirt, the snapshot of an instance is convert into RAW disk format even if the original image is a QCow2 image.
> Furthermore, the new image created by a snapshot take same 'disk_format' and 'container_format' as the original image. For example, a QCow2 image is instantiated and a snapshot of this image is created. The snapshot image is in RAW format but the metadata 'disk_format' of the snapshot image is 'QCow2'
>
> I think, nova-compute should not convert the image for a snapshot. If
> the image is in QCow2 format, snapshots are in QCow2 format also. If
> the image is in RAW format, the snapshots are in RAW format also.
>
> Perhaps, we can add a flag to force the snapshot format.
>
> Related question: https://answers.launchpad.net/nova/+question/167301
>
> I tested to change the command 'qemu-img convert' by : 'qemu_img_cmd =
> (FLAGS.qemu_img, 'convert', '-f', 'qcow2', '-O', 'qcow2', '-s',
> snapshot_name, disk_path, out_path)' in method 'snapshot' of class
> 'LibvirtConnection'. It works nicely.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/nova/+bug/824433/+subscriptions