@pedro_udifar Hi, Do you still have errors 500 when you are talking about general errors?

From reading the code with bad glasses rather than from knowing (out of my league, by far ) : my partial understanding is that full and incremental backups don't leave the host by the same route. FullXapi.mjs calls VM.export once and gets back a single XVA tar archive for the whole VM, while the incremental runner calls exportIncrementalVm per disk, and it's that per-disk call that carries the preferNbd option. Grep preferNbd across @xen-orchestra/backups and you get five files, all of them on the incremental side. So my guess, and it' a wild one, is that the two shapes just don't fit: NBD hands you one VDI at a time, and a full backup is asking for the whole VM in one archive. I've no idea whether anyone has looked at changing that, so might be worth a mention to @Team-XO-Backend, who would actually know.

Hi, Any detailed error log could maybe pinpoint the problem

@anthoineb, We checked both SMlog and xensource.log for the two latest incidents on hypervisor 172.30.50.181. There was no VM or storage pause/unpause operation before either stall. The only matching pause/unpause pairs were part of our later forced VM.hard_reboot: 2026-08-19, VM 172.30.52.185: stall confirmed around 20:24; pause at 20:36:37 and unpause at 20:38:12. 2026-08-20, VM 172.30.52.182: stall confirmed around 20:24; pause at 20:30:07 and unpause at 20:31:26. The first related VDI operations in SMlog were also the vdi_deactivate actions initiated by those reboots. Therefore, we do not see a pause/unpause immediately before or at the onset of either lock.

@pierrebrunet I built on the fix_undici_timeout branch and manually ran the metadata backup job 10 times and did NOT get an error. I will stay on this build through the weekend, let the scheduled metadata backups run, and report back on Monday.

Anyone who is using Commvault to back up VMs please tell me what you are using for credintials since you have to connect directly to a pool? I am looking for a way to backup VMs using Commvault and us AD accounts or OIDC.

Intel needs some special handling to support physical displays with PCI Passthrough; I don't know much of the details, but on "recent" machines, some bits are missing according to : https://lore.kernel.org/all/20260802050824.10554-1-brchuckz@aol.com/