OLVM: Incremental Backups for RAW DISKs

[rishibp]

Limitations for Changed Block Tracking

Due to oVirt KVM technical limitations, checkpoint IDs are not created for disks in the RAW format. Therefore, Veeam Backup for OLVM and RHV will not be able to use CBT when processing VMs with RAW disks attached. If CBT cannot be used, Veeam Backup for OLVM and RHV reads the whole content of VM disks and compares it with backed-up data that already exists in backup repositories. In this case, the completion time of incremental backups may occur to grow.

Will this limitation be resolved in near future? Any updates on this ?

[rovshan.pashayev]

Hi Rishi,

This limitation, as you pointed, is due to oVirt KVM’s handling of RAW disks, not Veeam Backup for OLVM. Veeam relies on oVirt’s capabilities, so any resolution would depend on updates from oVirt.

[gnantista]

Hi everyone, appending to this post to add one bit
I tried a backup of an OLVM VM with disks in RAW format.
I'm fine with having no-CBT backup, but as soon as I perform a restore keeping RAW format, it fails.
If I perform a restore changing disk format from RAW to QCOW2 it succeeds

Is it possible to restore a VM with RAW format disks keeping the original RAW format?
Thanks
G.

[rovshan.pashayev]

Hello Giuseppe,

Please open a support case so the support team can guide you with a solution for this scenario.

[rovshan.pashayev]

Hello Giuseppe,

The latest build, as seen at Current build is 12.3.1.1139 (March 19, 2025), includes a fix for this problem.

[gnantista]

Thanks Rovshan! Going to test it with my customer!

[gnantista]

Hello folks,
I want to give you some updates on this topic
We opened a support case, the issue was the hypervisor version, v4.4 while the minimum supported version is v4.5
Customer upgraded their cluster and the issue is solved
Thanks a lot for your support!
Regards
G.