Backup fails if VM has a USB pass through

[ghost]

Snapshot
Start: Nov 12, 2021, 11:48:39 AM
End: Nov 12, 2021, 11:48:39 AM
Error: VM_HAS_VUSBS(OpaqueRef:ecfe2189-5c1b-4b4b-807b-a856ef9ab6db)
Start: Nov 12, 2021, 11:48:39 AM
End: Nov 12, 2021, 11:48:39 AM
Duration: a few seconds
Error: VM_HAS_VUSBS(OpaqueRef:ecfe2189-5c1b-4b4b-807b-a856ef9ab6db)

Passed on as advised by xcp-ng.

[olivierlambert]

Well, the question is: what is the reason to prevent snapshot of a VM with USB passthrough? Note that we can export a halted VM anyway, despite having an USB passed. So I'm not sure to understand why we can't make a snapshot (even if the VM is halted).

[numo68]

+1 here. I have a VM running a home automation setup where the USB device is basically a serial port controlling some device - no state that would be missed from the backup there. I'd be fine with the passthrough configuration not being backed up, I can understand that this is something reaching out of the VM itself that is not easy to reconstruct on eventual restore, but making the backup impossible because of it is a major drawback.