Snapshots are alway made in raw and not qcow2

[Mark Donovan]

Hi,
I am using the same version of openstack in two deployments. When I take a snapshot in one environment its is saved in qcow2 but in the other it is saved as raw. The raw format saves an image with the size of the flavour. qcow2 format saves an image the size of the actual used disk space.

The version I am using of openstack is: Version: 2015.1.1

The version of Glance is: 0.17.1

I could not ascertain any difference between the glance configuration in both environments. The only difference is that the CEPH file system is used in the deployment where snapshots are saved in raw. However we are able to upload images in qcow2 nonetheless.

Thank you,
Mark Donovan

[Kairat Kushaev (kkushaev)]

Hello Mark,
glance does not convert images during the upload. It just stores bits.
If you look at the Ceph documentation looks like there is troubles with qcow2:
http://docs.ceph.com/docs/master/rbd/rbd-openstack/

Ceph doesn’t support QCOW2 for hosting a virtual machine disk. Thus if you want to boot virtual machines in Ceph (ephemeral backend or boot from volume), the Glance image format must be RAW.

So I guess nova(or Cinder or other component that provides bits for Glance image) always specifies RAW format always when ceph is used.

I hope this thread also help you.

[Kairat Kushaev (kkushaev)]

It doesn't look like bug in glance.

[Mark Donovan (mark-donovan)]

Hi Kairat,
OK so even though our images are stored in format qcow2 ceph is really
storing them in raw? Or do they only expand to raw when the images are
booted? So a 5.3 G qcow2 expands to the flavour size when it is launched?
Thanks,
Mark

On 04/29/2016 01:11 PM, Kairat Kushaev wrote:
> It doesn't look like bug in glance.
>

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