Single file restore sometimes works sometimes not works

[Seppi]

Hello,
we have a problem with the single file restore on our PMVE.

If we want a single file restore from our ProxMox Backupserver, sometimes works sometimes not works.

When we click restore a single files the files was downloaded but the file size has 0 KB.

Proxmox VE version 8.4.1
Proxmox Backup Server version 4.0.14
VM Windows Server 2019 size 1,6 TB

any idea?

 

[Onslow]

Hello, welcome to the Forum .
What is the original size of the file visible before restoring?
What does the task log contain?

 

[Seppi]

Thankl you,
the original size was 62 KB and the recovery log says Task OK.
We have this situation not on all files, sometimes works sometimes not works

 

[Onslow]

Is there any similarity or dissimilarity between the files which succeed and which fail?
Different intented restore location / OS / directory,...?
Anything that makes any schema?

 

[Chris]

Hi,

the original size was 62 KB and the recovery log says Task OK.

How did you verify this? Please perform a full restore of that VM backup snapshot and verify the file size there. Could it be that the file maybe was truncated to size zero at some point before being rewritten? Or that it was not yet written? E.g. contents might get written to a temporary file before being persisted to the final location. Or data might still be buffered before being written/flushed to disk.

 

[Seppi]

Unfortunately, no pattern can be recognized. The files are located on the same path in different directories. '
Some files can be restored, while others in the same directory cannot.

 

[Chris]

Do you have the qemu guest agent installed in the VM? Without that there will be no fs-freeze, so contents might not be synced to disk yet, see https://pve.proxmox.com/pve-docs/chapter-qm.html#qm_qga_fsfreeze

 

[Seppi]

Yes, the qemu guest agent are installed on all VM's