Windows deduplication, spanned volumes on dynamic disks and PBS...

[christophe]

Hi all,

It seems PBS 3.0 is able to file-restore files from a deduplicated ntfs Windows 2022 VM. This is great! PBS 2.x was NOT able to do so.
I haven't seen this feature in any doc yet, but more and more of our users are happy.
Is someone from proxmox team aware of that?

It seems PBS 3.0 is able to file-restore files from a spanned volume on a dynamic disk (ntfs again) Windows 2022 VM. This is great! PBS 2.x was NOT able to do so!
Is someone from proxmox team aware of that?

We haven't tried yet stripped volumes but may be are they also ok for a native file-restore with PBS 3.x?

It is not easy to find info on such features, neither at kernel level, nor at PBS level.

Can anyone confirm those facts?

So as of now, ReFS is the last remaining filesystem on Windows that needs a dedicated VM to restore files.

Thank you all, PBS is great!

Christophe.

 

[fabian]

the restore image kernel was updated for PBS 3.0, possibly the NTFS driver supports more features now..

 

[christophe]

So nobody was really aware...
Well, no problem : it works!

Christophe.

 

[hydrogencn]

So nobody was really aware...
Well, no problem : it works!

Christophe.

I've been trying to test with updated PBS (3.1-4) and PVE (8.1.10) as well, but using an existing backup of Windows Server 2019 with deduplication. It seems to still not be working. Did you use a fresh backup?

 

[christophe]

I've been trying to test with updated PBS (3.1-4) and PVE (8.1.10) as well, but using an existing backup of Windows Server 2019 with deduplication. It seems to still not be working. Did you use a fresh backup?

No, in fact it is not working with ntfs deduplicated volumes.
Some pve versions (depending on in kernel ntfs driver) gives an error when trying to restore, and latest versions gives no error but restored file is empty!

And don’t forget : dedup tasks on Windows volumes starts a few days after volume creation…

And bé avare that if you a restoring a file which is NOT deduplicated (on a deduplicated volume), il will work ! You need to verify in Windows if file size is very different than on disk file size!!

So one need to carefully verify what is truely restored, no error does not mean file restore ok!!!

Same problem with software raid on Windows volumes : if you are lucky and the file to restore is on the first stripe, it’s ok. If file to restore is on any other stripe, it will not work…


Christophe.