Hyper-V vm disks always restored as dynamically expanding?

[sjoerdkroes]

We found that, when restoring a Hyper-V virtual machine with fixed disks (VHD), Veeam Backup&Replication always restores the disks as dynamically expanding disks. The manual for Backup&Replication doesn't explain this in any way. The only reference I found is when exporting disk to Hyper-V formatted disk from Veeam Agent backups. It clearly states that disks are always exported as dynamically expanding disks. But this about virtual machine backups, not Veeam Agent backups.

When restoring VMware virtual machines, you are given the option in what format you want to restore virtual disks (thin, thick). What could be the reason this feature is not available when restoring Hyper-V virtual machines?

[wishr]

Hi Sjoerd,

The disk type is preserved. We've just checked that in our labs and the fixed disk was restored as fixed.

What kind of restore it was?

Thanks

[sjoerdkroes]

I used the option "Restore entire VM..." and then the option "Restore to a new location, or with different settings". There are no options to alter the disk type when restoring. Strange indeed...

[wishr]

Correct, there is no option to set a disk type to be different after recovery yet, so we consider this as a feature request for the future product versions. Following current logic, the initial disk type is preserved.

How you identified that the disk type has been changed?

[sjoerdkroes]

I identified this issue by using the "inspect disk" option on the original running vm. Hyper-V Manager says it is a fixed disk. Then, I do a restore of the vm to another Hyper-v hypervisor. After restore I use the option "inspect disk" again. Now, Hyper-V Manager says it is a dynamically expanding disk. The restored vm is running fine, but it does have another format for the virtual disk file.

[wishr]

Thank you. We'll try to reproduce it one more time. I'll report back with a result.

[sjoerdkroes]

I also tried an Instant Recovery and then a storage migrate from the same Veeam server. This time, the file format for the virtual were left intact. So it only seems to happen for me when I do a complete vm restore.

[sjoerdkroes]

Hello Veeam, did you already tried to reproduce this issue again and did you have other results than expected? Or do you think it is better to create an official support ticket for this issue? It's still something I would like to understand why this is happening in the environment I'm maintaining.

[wishr]

Hello Sjoerd,

Not results yet - most of the QC team members are currently busy with the next release, however, we have agreed that detailed testing of your use-case scenario will be performed. Since you are looking for a quick solution it would be better to raise a support case on this topic - our engineers will perform an initial analysis, collect some basic information about your environment, and possibly, shed the light on the situation. Please do not forget to let me know your case ID once raised - I'll keep an eye on it.

Thanks in advance!

[sjoerdkroes]

Thank you for the quick reply! I've now also created a case for this issue. The case number is 03858993.