Just go to Settings > Servers tab in XO and remove the entry associated with this pool.

@mjr99 I bypassed it weeks ago. Didn't have to downgrade netbox. At the time. I upgraded to the latest Xo from sources. Then netbox worked. I shall be upgrading xo soon again Thank you all.

@Pilow we really did only add one small log . we'll need to dive deeper for a real cause ( and fix)

@Andrew This was the exact problem I was facing. The affected VMs still had the guest-tools.iso mounted in the virtual drive. Once I ejected the ISO, I was able to clear the errors and the backup jobs resumed normal operation. For anyone else hitting this "stuck delta" or VDI_IN_USE state, here is the exact workflow I followed to resolve it: Shut down the VM (Essential to release all storage locks). Eject the ISO/CD from the VM console or CLI. Delete all snapshots associated with the VM (including any old or "ghost" backup snapshots). Delete the VM's backup folder from the remote SR/Backup target to ensure a clean metadata start. Monitor the Coalesce process (via SMlog) and wait for it to finish flattening the VHD chain. Power the VM back on. Manually trigger a Backup Job. Following these steps, the first run was (as expected) a Full backup, but every subsequent run has been a successful Delta with no "hanging" snapshots left behind.

@florent Thanks, if there is something I need to do to coalesce the vdis to avoid disaster, that would be good to understand. I had been thinking it was just an XO issue that would not affect running vms and their vdis.

The thing is that it works very well and doesn't need fixes… I know, not usual right? It was so stable that we left it like that waiting for people coming for bugs and nothing happened… We'll cut a 1.0 in the next weeks/months.

Instruction published: https://docs.xen-orchestra.com/sdn_controller#openssl-3--sdn-upgrade-path Any volunteer to test this along upcoming XCP-ng update ?

@afmart_dei could you share the /var/log/xensource.log of the joining host ? ideally the whole part after the host started (you could look at the file before rebooting and strip all lines before the last line you saw)