Hard reboot sorted itself out

@john.c said: nd need to be cleared, before re-attempting the update. Checking the logs will help Just for completeness... it kept doing this after all the typical diagnosis steps. So never found a solution Definitely wasn't cache or disc space related. In the end I built the XOA from source on the same VM and that worked fine. Although subsequent to that I've moved XOA to the containerised version thus saving an extra VM!.

@irtaza9 i would look a the usual suspect, /var/log/SMlog /var/log/xensource.log see https://docs.xcp-ng.org/troubleshooting/

@yllar Hello, We are still validating the ISOs, but we are getting closer to releasing them. We hope to make them available soon.

I have also opened a support ticket with Veeam. Well trying to... Issue with my account preventing me to and working to fix that issue. Veeam forum did make this statment about CBT and snapshots - There is one known snapshot issue that I'm guessing could possibly have this side-effect (noted in the release notes BTW). We take standard Xen snapshots for CBT but then immediately rename them with our own naming convention. We've noticed that sometimes this rename operation returns success status even if it fails. In this case I can see how this might throw this sort of error but again best to confirm w/support Veeam support ticket - 08188639 Update from Veeam - Thanks for the update I'm currently checking with my team and I will update as soon as possible, what I noticed in the debug logs is the following API failing \Backup\Plugins\XEN\Backup\Backup Job 1\Delilah ArcDC02 with debug enable 2026-08-07 20:05:04.067 00006 DEBUG | [BackupService]: <== Request localhost:19000, IsTaskFinished, body: {"taskId":"491371d9-4699-4087-b549-9862d2188177"} 2026-08-07 20:05:04.067 00006 DEBUG | [BackupService]: ==> Response localhost:19000, IsTaskFinished, success, duration: 0.1404 msec, body: false 2026-08-07 20:05:04.843 00019 INFO | [XenRpcClient]: Start ListChangedBlocks 2026-08-07 20:05:04.843 00019 DEBUG | [XenRpcClient]: <== Request https://192.168.20.3/Async.VDI.list_changed_blocks, body: ["OpaqueRef:b77ca409-d438-d97e-d8c3-f212647ad469","OpaqueRef:8c83f698-8836-3b4c-1506-8e97315aae1f"] 2026-08-07 20:05:04.845 00019 DEBUG | [XenRpcClient]: ==> Response https://192.168.20.3/Async.VDI.list_changed_blocks code: "OK", duration: 2 msec, body:{"opaque_ref":"OpaqueRef:c9389aa3-552a-0aa4-a5bc-f9b4f7a40e98"} 2026-08-07 20:05:04.845 00019 DEBUG | [XenRpcClient]: <== Request https://192.168.20.3/task.get_record, body: ["OpaqueRef:c9389aa3-552a-0aa4-a5bc-f9b4f7a40e98"] 2026-08-07 20:05:04.847 00019 DEBUG | [XenRpcClient]: ==> Response https://192.168.20.3/task.get_record code: "OK", duration: 2 msec, body:{"uuid":"72b5eb58-5053-d77a-9ee9-089ffaed4541","name_label":"Async.VDI.list_changed_blocks","name_description":"","allowed_operations":["cancel"],"current_operations":{},"created":"2026-08-08T00:05:04Z","finished":"1970-01-01T00:00:00Z","status":"pending","resident_on":"OpaqueRef:05e44734-86d0-c9f6-5079-25633df7bf06","progress":0.0,"type":"<none/>","result":"","error_info":[],"other_config":{},"subtask_of":"OpaqueRef:NULL","subtasks":[],"backtrace":"()","opaque_ref":null} 2026-08-07 20:05:04.848 00019 DEBUG | [XenRpcClient]: Current task Async.VDI.list_changed_blocks:72b5eb58-5053-d77a-9ee9-089ffaed4541. Status: "pending" Progress: 0 2026-08-07 20:05:06.848 00018 DEBUG | [XenRpcClient]: <== Request https://192.168.20.3/task.get_record, body: ["OpaqueRef:c9389aa3-552a-0aa4-a5bc-f9b4f7a40e98"] 2026-08-07 20:05:06.850 00018 DEBUG | [XenRpcClient]: ==> Response https://192.168.20.3/task.get_record code: "OK", duration: 1 msec, body:{"uuid":"72b5eb58-5053-d77a-9ee9-089ffaed4541","name_label":"Async.VDI.list_changed_blocks","name_description":"","allowed_operations":[],"current_operations":{},"created":"2026-08-08T00:05:04Z","finished":"2026-08-08T00:05:05Z","status":"failure","resident_on":"OpaqueRef:05e44734-86d0-c9f6-5079-25633df7bf06","progress":1.0,"type":"<none/>","result":"","error_info":["SR_BACKEND_FAILURE_460","","Failed to calculate changed blocks for given VDIs. [opterr=Source and target VDI are unrelated]",""],"other_config":{},"subtask_of":"OpaqueRef:NULL","subtasks":[],"backtrace":"(((process xapi)(filename lib/backtrace.ml)(line 210))((process xapi)(filename ocaml/xapi/storage_utils.ml)(line 150))((process xapi)(filename ocaml/xapi/message_forwarding.ml)(line 141))((process xapi)(filename ocaml/libs/xapi-stdext/lib/xapi-stdext-pervasives/pervasiveext.ml)(line 24))((process xapi)(filename ocaml/libs/xapi-stdext/lib/xapi-stdext-pervasives/pervasiveext.ml)(line 39))((process xapi)(filename ocaml/xapi/rbac.ml)(line 228))((process xapi)(filename ocaml/xapi/rbac.ml)(line 238))((process xapi)(filename ocaml/xapi/server_helpers.ml)(line 78)))","opaque_ref":null} 2026-08-07 20:05:06.850 00018 DEBUG | [XenRpcClient]: Current task Async.VDI.list_changed_blocks:72b5eb58-5053-d77a-9ee9-089ffaed4541. Status: "failure" Progress: 1 2026-08-07 20:05:06.850 00018 DEBUG | [XenRpcClient]: <== Request https://192.168.20.3/task.destroy, body: ["OpaqueRef:c9389aa3-552a-0aa4-a5bc-f9b4f7a40e98"] 2026-08-07 20:05:06.851 00018 DEBUG | [XenRpcClient]: ==> Response https://192.168.20.3/task.destroy code: "OK", duration: 0.735 msec, body:"" 2026-08-07 20:05:06.851 00018 ERROR | [XenRpcClient]: Failed ListChangedBlocks. Error: [Task 72b5eb58-5053-d77a-9ee9-089ffaed4541 (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]. Veeam.Vbf.Common.Exceptions.ExceptionWithDetail: [Task 72b5eb58-5053-d77a-9ee9-089ffaed4541 (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]. ---> Failed to calculate changed blocks for given VDIs. --- End of inner exception stack trace --- at Veeam.XenBackup.RestClient.XenRpcClient.GetTaskResult(XenRef`1 taskRef, CancellationToken cancellationToken) at Veeam.XenBackup.RestClient.XenRpcClient.<>c__DisplayClass94_0.<<ListChangedBlocksAsync>b__0>d.MoveNext() --- End of stack trace from previous location --- at Veeam.Vbf.Common.Helper.Retry.RetryHelper.ExecuteActionAsync[T](Func`2 asyncAction, String description, ILogger logger, LogLevel logLevel, CancellationToken cancellationToken) 2026-08-07 20:05:06.851 00018 INFO | [XenRpcClient]: Retry after 10 sec. Retry 6/10 for ListChangedBlocks There is a XEN forum and guide from him, but I need to check internally as first https://docs.xenserver.com/en-us/xenserver/developer/changed-block-tracking-guide/troubleshoot.html#you-cant-list-changed-blocks-between-two-vdi-snapshots CBT: the thread to centralize your feedback | XCP-ng and XO forum https://xcp-ng.org/forum/topic/9268/cbt-the-thread-to-centralize-your-feedback/364 Regards

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?

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 !

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

@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.

@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 !

Thanks for coming back with the actual cause instead of leaving it hanging. To me, a permissions reset on /etc/rc.d/rc.local would explain it completely, and it fails in the worst way, since nothing complains at boot and the VMs just never start. It also looks worth documenting, because our own troubleshooting page tells people to append a clocksource workaround to /etc/rc.local without mentioning the executable bit either, so anyone following that could end up with a workaround that quietly does nothing. I haven't tested whether the 8.2 to 8.3 upgrade resets that bit every time or just happened to in your case, so that half stays your finding, not mine. I'm curious what you turn up on the colon versus equals behaviour.