@acebmxer Thank you for your quick feedback.

@florent [image: 1785422247634-backup-metadados3.jpg]

Dry-run output [14:09 ovbh-pprod-xen03 ~]# python3 snapshot-fixer.py dry-run INFO:root:Regenerating database... INFO:root:The VM b532b6e3-df2a-42e2-ade1-ac424c782938 has Ref:1 as its "snapshot_of" value, changing to null. INFO:root:The VM 9707615f-334e-43bf-9946-95205bf8869f has Ref:1 as its "snapshot_of" value, changing to null. INFO:root:The VM 1555cf78-7546-2b86-771d-ee66a306faf3 has Ref:941 as its "snapshot_of" value, changing to null. INFO:root:The VM 99532d6b-a2e3-4133-8737-c416e8ef5bda has Ref:14 as its "snapshot_of" value, changing to null. INFO:root:The VM 9b7d927c-b70d-27f3-5d08-100d0744780f has Ref:50 as its "snapshot_of" value, changing to null. INFO:root:The VM a04e5d4a-1067-4f91-89d7-8b5addb205f2 has Ref:1 as its "snapshot_of" value, changing to null. INFO:root:The VM 2b712337-b1e6-1b0f-d39e-5f3803bd8643 has Ref:9 as its "snapshot_of" value, changing to null. INFO:root:The VM 5b5c6ae6-2c9c-d76f-d9ae-7eff962287f0 has Ref:20 as its "snapshot_of" value, changing to null. INFO:root:The VM d155c631-b18f-c0d2-b425-49d53ed065fb has Ref:90 as its "snapshot_of" value, changing to null. INFO:root:The VM 8c0a4696-4ea7-34b2-ca14-0252b4d6e357 has Ref:243 as its "snapshot_of" value, changing to null. INFO:root:The VM c23a131e-e724-7f02-adba-e199526b401d has Ref:20 as its "snapshot_of" value, changing to null. INFO:root:The VM 5a2311cd-bbb7-6444-0119-9bb8c8a9e593 has Ref:265 as its "snapshot_of" value, changing to null. INFO:root:The VDI 5a6c334e-040e-4825-9ced-55ee2b17aac6 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI f887e9da-cda5-496e-9040-57aab22e510a has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI a3406a09-928a-4bf1-b558-53ab744dc41b has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI ea9d191b-0a2d-49d5-a046-7ebe483993fa has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI eca38833-219e-439a-91ac-d3321772f71a has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI dc740184-28b4-4db5-938b-837234f08290 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 1ee50d61-1426-4322-892b-e270cfd4c97e has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 5488fdac-d7cf-4fc0-ac0f-535a36bf93d6 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 7bc9add5-cf5d-49c6-8022-78fb386a1e3b has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 91f43c21-07ba-426f-a146-2d678e7de83b has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI a8dd3a48-8035-4a49-90f6-d91acdbbb032 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 7f128b35-5e6f-4e32-b0c8-15059878c10c has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 5235fea0-4f20-4f19-859a-044b99ebce3c has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 52e7b2de-84cb-4e1b-9a1f-4b898399a650 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 2418d9e7-c3a7-424a-af36-fd983d438163 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI c7fc59e4-8d90-4157-b526-bc5ecc549b66 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI fd507e6c-c3e2-4305-81c8-f92da2703db9 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 70081652-9efd-4881-85b6-c39b0de6f90b has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 5bf279c2-cff6-4eb6-8e70-376467d649f6 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI b37f9db8-b2bc-42d1-88b5-10207f9aeeb2 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 07f430b2-c7f1-41d8-bd9f-2fe67f4f458b has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 25937e64-4344-4772-8d8b-b5e9fee7cd81 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI cd0511c9-b803-48f2-afae-35fa51225c9e has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI c7063926-088b-4cf0-8004-d75ea15653c5 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI aff3122f-1693-4371-8d6f-5a2975aec85d has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 17200bad-cc3e-4b5d-9844-d1e56604d2a3 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 99ad1143-0b88-46f0-ac0e-e5a72b69f327 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 55c5e0a1-0af7-4b36-b5a6-57cff1185208 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 2c5dec71-cd9a-4208-9e96-922b44544d09 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 27ccf472-3fa9-4d23-bdb1-6ca70f570230 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI e95206e0-4940-48fc-8564-238f2f0f6440 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 5544ccc6-dec4-4528-91b4-302a6552146b has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI d1f154d5-9bdf-4c01-897c-367863efe114 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 2476d6b3-1b25-47ca-bc8d-869125eed779 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI a4fc211d-9e68-4f7c-99e5-170f3786ad55 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 2ce4926e-c8dc-4185-bbb4-ce887ef78b42 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 09ee300e-ac03-48f8-a6cc-bc33398fd75f has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 1516113c-9dbd-4e23-b76d-e1ec8cbed0c0 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 78a67732-4889-4053-8a36-fb5d3cf1c0d3 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI ad9b1572-a29d-42bb-842d-448e49bdbbb2 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI c2ae7055-dbc8-4d74-8174-88e6b6c9dbb4 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 03e6c2ec-c8bc-4bc3-b274-654e67e52ba7 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 60ad964b-b5aa-4077-9ca0-6acb84cbea15 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 6cfe58b0-3dd7-422d-924c-284d811afa97 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI bde8b13b-2f8c-454a-8bae-6f07fa907b9f has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI a9c40305-9f7c-4af9-be56-b1dd4f26458c has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 71c5c06b-a38a-4dc8-b4eb-8a3bfafdd271 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI bc31eab4-7720-45fb-b6e8-23d529381221 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 6a1ff504-f448-420a-ba4b-8a05d8a3f2da has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI cbaf2499-489f-4b48-a017-e48fb73b4987 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI bd2b4490-3464-4650-8847-11a376393ae9 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 7520b2ae-a236-4065-8ec7-ac2cfa37a5a6 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 8874451d-249f-4913-ad9c-fb8da214f663 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI a05390d4-5ef7-458d-b090-799215c49c6e has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 1e949f7b-3f04-4fcc-bdc9-2052974aef34 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 156877f1-0701-484e-9c60-659841110d38 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI ab4c71e6-ac41-4fc6-8435-546ab827c728 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI bb36c707-d6a9-4811-b3dc-33c694b2faf8 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 5df27f53-4a98-41ba-b577-7468e3eb9557 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI cd158763-7f28-42ca-bddb-30ffcc89e18f has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI b741152c-ce78-4d00-8227-2031ba3778bc has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI c8a5ba4e-4140-4c4c-b272-9b44e4cd8dae has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 450bddc9-946f-43c1-b9a3-5f50678ac249 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI d07a41d6-0aa2-49a5-a241-b755c6daa3d8 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 415196a5-de15-4a2a-912a-675f804af98e has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 31ecf300-cc63-4845-8e7c-d191f4042135 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 357c608a-a805-48ab-8a96-d93fe1157304 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 0eb9747b-02d3-4cd9-8dbb-d0a7d8a538e0 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 5111fe82-17b7-467c-851c-82ccb18d7bb1 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 653f53d3-1e8b-41e7-a997-41025bc268ef has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI aa0fdf8f-0a1f-4c1e-8b31-c36ea0343775 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 0a5aefe2-0f59-4447-b7ba-c8e9c4a97f67 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 832e9bfd-899a-41e3-baa6-373175b4b0ec has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 55300191-34ec-4252-aa9f-3b2bdd5f98c7 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI d55536f8-906e-419e-a17a-318095312563 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 7884662d-967e-43b1-a789-e92c1c149403 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 09d26ac2-82a5-4208-8ebc-9d0df97665fc has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null. INFO:root:The VDI 848ff799-092f-428b-90de-3a85517c7315 has OpaqueRef:780aa24c-76c2-90c1-47d6-c4059770196c as its "snapshot_of" value, changing to null.

5 nbd connections went fine. 8 is not.

Glad the start-delay removal got that VM going again. I checked and it's a real, documented XCP-ng parameter, "the delay to wait before a call to start up the VM returns", so that explains the behavior. I couldn't find auto_poweron_delay documented anywhere in the XCP-ng or XO docs, so I'm not sure if it's something XO's advanced VM settings expose under a different name, or something unrelated you picked up while googling. If you check the VM's Advanced tab in XO and see what's actually set there, that would help pin down which setting you're really dealing with. Either way this looks like a gap in the autostart guide, since it doesn't mention that start-delay can interact with autostart at all.

Excellent! It's really cool to see how XO Backup and Replication can help you to migrate easily

Hey, thanks for writing this up with the actual commands and the screenshot, that really helps. Not sure why rc.local + vApps stopped working after your 8.2 to 8.3 jump. rc.local is more your own dom0-level script than something XCP-ng promises to keep stable across releases, so something underneath may well have shifted, but I can't point to what. On the delay question, there does seem to be a per-VM "start-delay" parameter. I ran into it replying to a pretty similar issue a couple days ago, if you want to compare notes: https://xcp-ng.org/forum/topic/12388. There are also the "appliance" CLI commands, the vApp equivalent, though from another recent thread it looked like nobody's fully sure how start order and delay actually interact there: https://xcp-ng.org/forum/topic/12149. So I think the capability is there, just not pulled together in one place. The colon-vs-equals thing is interesting. I honestly don't know xe's map-param parsing well enough to say if that's expected or a rough edge. Maybe someone closer to the CLI internals can say whether it should just reject that instead of creating duplicate entries. Given how scattered this all is, might be worth flagging to @Team-Documentation-Knowledge-Management. Hope some of that's useful, others probably know xe's internals better than me though.

I think this is fixed in 6.7: when a delta backup falls back to a full, the task now shows the actual reason instead of just contradicting itself the way you and Andrew both saw (PR #10148). Worth checking after you upgrade.

Both things reported here look fixed in 6.7: the retry succeeding but the job still showing as failed (PR #10129), and the EEXIST: file already exists error, which happened when a job got recreated after a crash (PR #10139). Curious if upgrading clears it for you all too.

The progress bar issue you and Florent were chasing looks fixed in 6.7 (PR #10133). Worth upgrading and seeing if it moves now instead of sitting still. Separately, since this thread is specifically about QCOW2 backups: 6.7 also fixes an offset bug that could leave incremental backups mostly empty after the first block when NBD isn't enabled. Worth a look at the release notes if that's your setup too.

Hello, You can find all the demo dashboards at the following address: https://github.com/steeve-san/OpenMetrics_XCP_Grafana Regard,

This issue should be fixed in the latest release (to be out today).

Hello @anthoineb, We captured another occurrence on the same VM, os-ott-data-3-2 (172.30.52.193), on the same hypervisor and QCOW2 VDI as the incident reported on 2026-07-25. This occurrence is useful because xen_blkfront.max_ring_page_order=3 was definitely active: xenstore showed ring-page-order=3 with eight ring references; the guest queue depth was 256; 255 write requests remained in flight; all 256 blk-mq scheduler tags were busy; wbt_lat_usec=0; I/O PSI full was approximately 98%; completed xvdb counters did not advance between samples. The backend state was nevertheless the same as in the previous capture: tapdisk was sleeping in scheduler_wait_for_events(); tap-ctl reported reqs_outstanding=0; tap request counters were 0/0; req_prod=0 and rsp_prod=0; no tap, image, VBD, map or xenbus errors were reported. One detail may be relevant: GDB still printed n_reqs=32 and n_reqs_free=32, although the frontend had negotiated an order-3 ring and the guest exposed 256 tags. Is this expected because n_reqs represents a separate fixed tapdisk request pool, or could it indicate that tapdisk is not observing the complete multi-page ring? The controller captured GDB and the guest/hypervisor state before reboot. After the ten-minute diagnostic window, the same signature was confirmed three more times and the VM was rebooted. It rejoined the cluster successfully. I have attached: the complete GDB/tap-ctl capture; the guest blk-mq, diskstats, PSI, D-state stack and kernel-journal snapshot; the corresponding tapdisk/xenstore, daemon.log and SMlog excerpt; a README and SHA-256 checksums. The important new result appears to be that increasing max_ring_page_order from 0 to 3 did not prevent the stall; the same mismatch recurred with 255/256 frontend requests/tags occupied while the backend ring and tapdisk remained empty. 20260730-005220-gdb-172.30.52.193.txt 20260730-pre-reboot-guest-172.30.52.193.txt 20260730-pre-reboot-hypervisor-172.30.50.191.txt README.txt SHA256SUMS.txt