On Thu, Jul 7, 2022 at 12:40 AM Jonas <jonas@rabe.ch> wrote:

Hello all

I'm trying to create incremental backups for my VMs on a testing cluster and am using the functions from https://gitlab.com/nirs/ovirt-stress/-/blob/master/backup/backup.py.

Note that the VM configuration is not backed up, so restoring
requires creating a new VM with the restored disks.

So far it works well, but on some disks it is not possible to enable incremental backups even when the VM is powered off (see screenshot below). Does anyone know why this might be the case and how to activate it? I think I already checked the docs and didn't find anything but feel free to nudge me in the right direction.

It look like you try to enable incremental backup *after* the disk was created
which is not possible if the disk is using raw format. I guess the disk is on
file based storage (NFS, Glsuter) and thin volume on file based storage is
using raw format by default.

The way to fix this is to convert the disk to qcow2 format - this feature
is available since ovirt 4.5.0, but it works only via the API/SDK.

Here is and example code for converting disk format:
https://github.com/oVirt/python-ovirt-engine-sdk4/blob/7c17fe326fc1b67ba581d3c244ec019508f3ac25/examples/convert_disk.py

The example is not finished and is still in review, but it should show
how to use the API.

Nir