Error with file restore on pve with pbsbackup

[Dark26]

We try to restore a file from pve with a pbs backup and, the file downloaded is zero byte size.

Sometimes after 3 or 4 try, the file is download and sometimes not.

The disk is a windows ntfs ou linux

it seems the is no linr in the log when the restore failed.

We try windows and linux instance and we have the same beahavioer.

We try with two differnet pbs ( one is the replica of the other), same result.


pveversion :
pve-manager/9.2.4/5e5ae681198514d4 (running kernel: 7.0.14-4-pve)
pbs version :

 proxmox-backup-manager version --verbose
proxmox-backup                       4.2.0         running kernel: 7.0.14-14-pve
proxmox-backup-server                4.2.5-1       running version: 4.2.5       
proxmox-kernel-helper                9.2.0                                     
proxmox-kernel-7.0                   7.0.14-15                                 
proxmox-kernel-7.0.14-14-pve-signed  7.0.14-14                                 
proxmox-kernel-7.0.14-12-pve-signed  7.0.14-12                                 
proxmox-kernel-6.17                  6.17.13-21                                 
proxmox-kernel-6.17.13-21-pve-signed 6.17.13-21                                 
proxmox-kernel-6.14                  6.14.11-9                                 
proxmox-kernel-6.14.11-9-pve-signed  6.14.11-9                                 
proxmox-kernel-6.14.8-2-pve-signed   6.14.8-2                                   
ifupdown2                            3.3.0-1+pmx12                             
libjs-extjs                          7.0.0-7                                   
proxmox-backup-docs                  4.2.5-1                                   
proxmox-backup-client                4.2.5-1                                   
proxmox-enterprise-support-keyring   1.1                                       
proxmox-mail-forward                 1.0.3                                     
proxmox-mini-journalreader           1.7                                       
proxmox-offline-mirror-helper        0.7.4                                     
proxmox-widget-toolkit               5.2.8                                     
pve-xtermjs                          6.0.0-2                                   
smartmontools                        7.5-pve2                                   
zfsutils-linux                       2.4.4-pve1

Any idea?

 

[kawano-y]

Hi,

As a troubleshooting step, you may want to try restoring the same file from the command line using proxmox-file-restore.

This could help narrow down whether the behavior is specific to the web UI/download path or also occurs when using the file restore mechanism from the command line.

If the restore works reliably from the CLI, it may point more towards the PVE web UI, browser, proxy, or network path.

If the same behavior can also be reproduced from the CLI, it may point more towards the file restore backend, PBS access, or the backup metadata.

Thanks.

 

[Dark26]

i have this message in the /var/log/proxmox-backup/file-restore/qemu.log

[2026-09-07T08:00:26.920Z INFO  proxmox_restore_daemon::proxmox_restore_daemon::watchdog] Inhibit added: 1
[2026-09-07T08:00:26.921Z ERROR proxmox_restore_daemon::proxmox_restore_daemon::api] file or dir streaming task failed - Operation not supported (os error 95)
[2026-09-07T08:00:26.923Z INFO  proxmox_restore_daemon::proxmox_restore_daemon::watchdog] Inhibit dropped: 0

 

[Dark26]

with the comman line i have this error if i try to copy a file from where the partition is mount :

i see the file like in the gui but if i try to copy a file :

 cp toto.pdf /root/
cp: erreur de lecture dans 'toto.pdf': Opération non supportée

I lauch a verification of the backup, and no errors found

 

[steve999]

That "Operation not supported (os error 95)" is EOPNOTSUPP, which is a useful clue. The restore daemon VM mounts the backup and the kernel refuses a specific operation on that file, so this looks less like corruption (verification passing supports that) and more like something about the files themselves that the restore kernel does not implement.

Since both your PVE hosts and both PBS servers reproduce it, I would look at per-file attributes before digging deeper into the daemon. If the source VM is Windows/NTFS, check whether the affected files are compressed, sparse, or OneDrive "Files On-Demand" placeholders. Those are reparse points and are a classic cause of "operation not supported" when a non-Windows copy path touches them. From the source machine, fsutil reparsepoint query <file> will tell you, and compact /u <file> removes NTFS compression. A whole folder synced by OneDrive would neatly explain why it happens across different VMs and PBS instances.

A quick control test helps too: drop a plain text file next to a failing one, run a new backup, and try restoring just that file. If the plain file comes through while the other fails, you have confirmed it is attribute-related rather than a problem with the web UI, proxy, or the restore daemon itself.

If it turns out to be reparse points, the practical workaround is a full VM restore or cloning the affected files to plain form at the source. Would be curious what fsutil says on one of the failing files.