So I ended up going with the Windows B&R as i could net setup the windows mount server when setting up the repo for the backups. It would setup the linux one but not the windows one. This was with using the veeam console from a windows client. So i ended up with the Windows one. Now after a few backups i am see this warning / error.... 8/5/2026 5:34:50 PM Warning : Failed to use CBT: [Task e75c4247-2ee1-7b51-088c-b970ace60f3d (Async.VDI.list_changed_blocks) failed: . SR_BACKEND_FAILURE_460. . Failed to calculate changed blocks for given VDIs. [opterr=Source and target VDI are unrelated] First i thought it was because i maped the new job to older backups from Beta v1. So i purged all old backups and started fresh. The full backups were successful. Now on first delta 4 out of 7 vms have that warrning. This a Veeam issue or xcp-ng?

@msupport said: The CBT metadata VDIs remain as snapshots, but their VHD parent references point to nothing. The tapdisk crashes, the VM loses disk access, the filesystem becomes corrupt. For VM-A (SQL Server), both disks (60GB + 80GB) have broken CBT snapshots. virtual-size=0, physical-utilisation=0. For VM-B (File Server), the 80GB disk has a broken CBT snapshot. Interestingly: virtual-size=85899345920 (80GB, same as the base disk) and physical-utilisation=8388608 (8MB). This is different behavior from VM-A — possibly a different code path in the CBT lifecycle. In my testing i did see similar issue Edit - updated with actual error message from what I am getting. The first full backup were all successful. This first delta backup have 4 vms with this error. The first time I saw similar was only 2 vms. 8/5/2026 5:34:50 PM Warning : Failed to use CBT: [Task e75c4247-2ee1-7b51-088c-b970ace60f3d (Async.VDI.list_changed_blocks) failed: . SR_BACKEND_FAILURE_460. . Failed to calculate changed blocks for given VDIs. [opterr=Source and target VDI are unrelated] For me i took it as because i original had backups from veeam 12.x the first xcp-ng beta. Pointed new backups from 13.1 to older backups. I then purged all older backups and started with a fresh backup chain. I ended up reverting to the windows base as i was not able to get the windows mount server setup. This was setting up from a windows client using the console to setup the repo.

i switched one of the backups for my extra pool from nfs to smb and its been sitting so i expect it to fail. might be a smb issue. ill update this post with results once it either fails or works [image: 1785952420501-2d4d9b1d-9aa5-4f1d-a1c1-d8ea5e079047-image.jpeg] i did test smb and it works. back to nfs works [image: 1785952526594-b2b807b8-d422-4719-8088-817b08d3c5ad-image.jpeg]

What kind of storage are you using? Is it a 4K block native storage? You should be able to see if you can create a virtual disk easily with xe vdi-create name-label=test virtual-size=1G sr-uuid=356475ac-…

Hi, I found your original request. I will make sure someone from the Sales team responds ASAP. Regards, Dan

If i recall from my migration I belive thats all there is to it. I know the docs mention about doing a test migration but mine just migrated and it just worked as you stated after making the needed adjustments. Let other chime in but i think you are good to go. And you could delete the snapshot from the vm.

Very cool, thanks for the feedback @maximsachs !

@jeremie1977 Ah, oui effectivement je n'ai pas testé avec plusieurs disques ! Et j'ai du typo dans la doc, je vais faire une PR pour modifier Je pense que c'est du a la façon d'insérer les disques et les DVD coté XCP-ng. Je vais investiguer !

This might have worked, at that time i've allready created new VMs from the information inside the Backup xml file. It worked out allright but building VMs this way, is quite tidious. Maybe there could be a way to find the correct installer and patches, to get a new host in a state to restore a pool backup, would be good.

Hi! No, but check XO logs/output to see what's going on

Filed both XO related issues: Memory visibility at VM creation: https://github.com/vatesfr/xen-orchestra/issues/10225 domain_crash invisible in XO: https://github.com/vatesfr/xen-orchestra/issues/10226 Linking to this thread as promised earlier, thanks all. Hope this helps someone out.

@poddingue, that is true, my first post here. I'll try to play with these BIOS settings again. and keep you posted. Cheers

Drivers are actually in @Team-Hypervisor-Kernel scope nowadays

More options: to Prevent overwriting the file: Method 1: Probably the best option. Use a Configuration Directory. Modern OpenSSH versions (8.2+) support an include directive. This is the cleanest approach. Create a drop-in file: Put your custom settings in a separate file, such as /etc/ssh/sshd_config.d/custom.conf. The rule: Package updates will not touch files inside this directory. Verification: Ensure the line Include /etc/ssh/sshd_config.d/*.conf is active at the top of your main /etc/ssh/sshd_config file. Method 2: Lock the File (Alternative) You can force the filesystem to make the file immutable so nothing can change it. Lock the file: Run sudo chattr +i /etc/ssh/sshd_config Unlock for edits: Run sudo chattr -i /etc/ssh/sshd_config when you need to make intentional changes. Method 3: Tell Apt to Ignore Updates. If you are on a Debian-based system, you can force the package manager to always keep your local version. Add this line to /etc/apt/apt.conf.d/local: UCF_FORCE_CONFFOLD=true

@poddingue Borrow away - "smoke alarm" is a better name for it than anything we had, so we might borrow it right back. Since you mentioned reading the matrix - here is the classification you would be reading, straight from the file: grep access: dadl/xen-orchestra.dadl | sort | uniq -c 49 access: admin 21 access: dangerous 122 access: read 75 access: write 122 of the 267 tools are plain read - that is the entire surface a review-capped agent gets. The other 145 exist in the same file, but for that agent they might as well not. The whole security taxonomy is greppable plaintext - which is rather the point of a declarative format. And if anything in the matrix looks wrong or missing, this thread is exactly the right place - real-world corrections are how it improves.

My earlier wording was the problem here, not your reading of it. There are two official descriptions and they do not say the same thing. The CLI reference calls start-delay "the delay to wait before a call to start up the VM returns", which is the one I quoted. The XenAPI field description calls it "the delay to wait before proceeding to the next order in the startup sequence". That second one is exactly what you saw: the delay lands on the next VM to start, not on the one you set it on. I quoted the confusing one and then said it explained your behaviour, which it does not really. What I still cannot explain is why a start-delay would stop a VM autostarting altogether. Neither wording predicts that, so I would rather say I do not know than invent a reason. On auto_poweron_delay, I went looking and could not find it anywhere in the XCP-ng or XO docs, so I think your instinct about that search result was right. I have updated the docs PR I had open so it leads with the XenAPI wording and cites both, since the CLI reference phrasing is what sent me wrong in the first place.

@yannsionneau , may this link helps if you not anyway know it https://medium.com/@timemaster5/getting-amd-phoenix-igpu-passthrough-working-on-xen-xcp-ng-8856593f9c0d I will give it a try this weekend

@oliv77 said: Hi, XOA version: xo-server 5.193.1 xo-web-premium 5.191.0 We've noticed on our production XOA server that when we put an XCPNG host in a pool into maintenance mode, we reboot it and then it reconnects to its pool but is no longer in maintenance mode. Is it possible to configure the XCPNG hosts so that they automatically return to maintenance mode after a reboot? Regards, Oliv77 Hi @oliv77, XO 6.7 - latest - adds this option in REST API and next month we should have the available action (Disable host and evacuate VM) in XO6 !