@poddingue Thank you!

Hi @Razielh, I think that error may be the 2 TB VHD ceiling, and it should go away if the backup repository is in block mode. The same thing came up in July on GitHub (https://github.com/vatesfr/xen-orchestra/issues/10193, a 6 TB qcow2 disk), where @Florent explained that a repository not in block mode writes each disk as one whole VHD file, which can't go past 2 TB. The reporter made a new share on their NAS, added it as a remote with "Store backup as multiple data blocks instead of a whole VHD file" ticked, and the 6 TB VM backed up after that. The docs say it too, though as a bullet in a list rather than as a hard limit: https://docs.xen-orchestra.com/backups-and-dr/backup-features-and-settings#remotes. While you're in there, incremental backups of qcow2 disks also need NBD on the job, or every run falls back to a full one (https://docs.xen-orchestra.com/backups-and-dr/backup-types/incremental_backups#nbd-enabled-backups); I haven't seen your job settings, so ignore that if it's already on. I'm not sure an existing remote can be switched to block mode in place, so a fresh share like in that issue seems the safer bet. Might also be worth a mention to @Team-XO-Backend that XO could say this up front instead of throwing a RangeError mid-transfer.

@MrQ said: @jr-m4 thank you so much for testing this updated driver. Just to make sure, I understand now that you confirm the driver is working as expected and the issues you had were not related to it? Or are there any problems still with this new driver? Many thanks again for spending the time to test and report. Hi Yes. I believe I was chasing a red herring of my own doing. I have not found anything actually problematic with this driver at all.

Thanks for the heads-up. If you built XO from sources, the docs say to keep Node on the latest LTS (https://docs.xen-orchestra.com/getting-started/install-from-sources#nodejs), so it's worth moving to the patched release on whichever line you run. For XOA, I don't know how fast the appliance picks up a new Node release, but I know something's cooking.

Hello Christof, Swapping the disks between the two VMs shows the problem follows whatever runs inside, not the VM itself. Next I would run xe vm-param-list uuid=<vm-uuid> on the host once with HAOS booted and once with Debian booted, and diff the two outputs. Fields like os-version, PV-drivers-version and networks are reported back by the running OS, so they change with the guest. My guess, and it's only a guess, is that one of them comes back in a shape Commvault's parser doesn't expect: "input string has the wrong format" is what .NET says when it fails to read a number. If you find the field that differs, Commvault support would have something concrete to work with.

OK, marking this solved... It was the phantom reboots causing issues because the tools were not fully installed, only thing I can't understand is why only 2 out of 3 Windows servers would quit. Any way, got the Xen Tools updated and a couple reboots later, everything is working again. Also I can now report that a bug that was fixed maybe a year ago is confirmed to work in my system. The bug was backing up a Windows VM that had a lot of empty space in the drive (over 250GB free) and turning on compression. It would time out counting zeros because it thought the process wasn't doing work. Both of these VMs are now compressing with zstd, one of them is substantially smaller now, the other only shrunk about 20GB. Because of the way Windows uses the drive, these are all full backups. The differential never seemed to be small because Windows does a lot of changes on the drive (there is a post about this somewhere in here from Olivier).

The UEFI and possibly SecureBoot requirements on a lot of stuff and going to turn a lot of old systems into garbage. Also going to be an issue when more current stuff gets upgrade from 8.3 in BIOS mode to requiring UEFI for version 9. That's the boat I'm in for production. Alma and openSuse may be a few of the last holdouts allowing v2 and BIOS boot.