Please disable HA and report if you still have the issue.

Following up since the situation changed: QCOW2 went GA in XO 6.5 (released 2026-05-28), so the old ~2TB VHD ceiling is gone. A disk at exactly 2TB, and well beyond it, is fine now without shrinking to 1.99TB first. When acebmxer and john.c replied, it was still a release candidate; it's the stable story now. I haven't migrated a disk quite that size myself, so I won't promise it's totally painless, but the format limit that was blocking you isn't there anymore. The release blog has the details if you want to read up before the migration: https://xen-orchestra.com/blog/xen-orchestra-6-5/

Bit of a necropost on your necropost, but this got easier in XO 6.5. The REST API now accepts a txChecksumming parameter when you create a VIF (PR #9793, https://github.com/vatesfr/xen-orchestra/pull/9793), and it maps straight onto the ethtool-tx / other_config value you were setting by hand. So, for new interfaces, you can do it through /rest/v0 now instead of the XAPI script. I think it's on the create path rather than existing VIFs, though, so for the firewalls already running your script or the gear icon is probably still the way, and I haven't tested it against a live VIF myself. Either way, it's nice to have it native in the API now. All-Ki opened this pull request in vatesfr/xen-orchestra closed feat(rest-api): add support for txChecksumming and rateLimitting on V… #9793

Hi @r0123456789, GET /rest/v0/hosts/:id/stats is available in the REST API

Hi @dan89, It is possible to create an authentication_token using the REST API. POST /rest/v0/users/me/authentication_tokens

Hi @Steve_Sibilia, FYI, ACL V2 / RBAC is now available in the REST API. You can see the RBAC doc. A dedicated thread is available on the forum thread, please feel free to share your feedback. Thank you.

@dinhngtu said: I've taken a quick look, looks like it'll be solved as part of the Windows guest agent overhaul, so please look forward to that. Thanks for the info. I will be looking forward to that, indeed.

@florent Thanks for your reply! We have started to migrate thousands of VMs, so disk transfer speed is important for us.. We will also do our detailed tests soon with different threads setting and publish it here. I think threads=1 is a good and logical default, but not efficient. Others might complain if you set it to a higher value. Configuration option would be a real good solution.

Another confirmed data point, with package delta and the specific malformed field. Host: XCP-ng 8.3.0, xapi 26.1 (build 26.1.4), Xen 4.17.6-9. Setup: XO from sources (community). All VDIs vanished from the per-VM Disks tab (XO 5 and XO 6); xe and the SR Disks tab show them fine; VMs run normally. Trigger was the 8.3 host update + reboot this morning — XO build unchanged since May 28, disks visible yesterday. Host update delta (today): all 26.1.3-1.10 → 26.1.4-3.1 (xapi-core, xenopsd, sm-cli, sm-fairlock, xapi-storage-script, vhd-tool, message-switch, etc.), plus sm 3.2.12-17.8 → 17.9 as an independent bump. The malformed field. An affected live OS disk (VM running): is-a-snapshot: false snapshot-of: <populated, points to another VDI> snapshot-time: <populated> A normal base VDI should have an empty snapshot-of. After the update, snapshot-of/snapshot-time are populated on real, non-snapshot base VDIs, and XO filters anything with a non-empty snapshot-of out of the per-VM Disks view — which is the disappearance. The VDI that snapshot-of points to is a legitimate base image in my environment (a heavily-reused Win2022 build template with a large genuine snapshot/clone lineage), so I can't tell from the host side whether the parentage links themselves changed or only the snapshot-of on live VDI labeling did. Either way, the consumer-visible effect is the same. REST confirms: /rest/v0/vms/<uuid>/vdis → []; /rest/v0/vdis/<uuid> → "no such VDI" for the VBD's referenced UUID, while xe vdi-list shows it. Caution for others: since live disks now carry snapshot-like metadata, be careful with Health-dashboard "orphan" cleanup and snapshot deletion on affected VMs until this is understood. Workaround that restored the per-VM Disks view: snapshot → revert → delete-snapshot (tested on a powered-off VM, immediate). Happy to provide more diagnostics. Quick Follow-up: Additional symptom, same root cause: ISO-SR VDIs are also affected. Pre-existing ISOs disappeared from the XO ISO picker (only ISOs uploaded after the patch still show). An affected ISO's vdi-param-list shows: is-a-snapshot: false snapshot-of: 937c3945-... (same anchor UUID as an affected VM disk on a different SR) snapshot-time: 19700101T00:00:00Z (Unix epoch — clearly synthetic) Notably the spurious snapshot-of on both an ISO VDI and an unrelated VM OS disk points to the same anchor UUID, with an epoch timestamp — so this looks like the update is stamping pre-existing VDIs with a bogus snapshot-of rather than any real lineage. VHD chains/GC are clean (GC reports no work).

@mdm Similar to the name-description parameter, the CLI ignores this parameter. The expected way to use would be to set the field value after the SR has been created. I'll make a work item to change the CLI and warn of ignored parameters so confusion like this doesn't happen

@pdonias confirmed... [image: 1780065202934-screenshot-2026-05-29-103255.png]

Hi @halvor, FYI, ACL V2 / RBAC is now available in the REST API. You can create a privilege that only give you read privilege on your host. You can see the RBAC doc. A dedicated thread is available on the forum thread, please feel free to share your feedback. Thank you.

I'm waiting for veeam 13.1 release as well. Will move a few things over and test out the native backup in the meantime.

It hurts (4y ) but I'm glad we finally managed to get what you needed!! Thanks for posting a comment in here after all this time [image: 1779991585587-21cd8648-f61e-46d9-a52f-4ec55a7b7c8b-image.jpeg]

@yllar I'm not sure honestly (I will have to ask the rest of the team), but anyway, even if it were fixed by latest xen package, we still didn't publish a new installer ISO with the fix. Target is still around June for the new ISO. Regards, Yann

@pierrebrunet I inadvertently found more information yesterday. I installed an old e492b commit on a new machine, configured identically to the original, and got a different error but the same effect. The new error is: xcp xo backup Error: read ETIMEDOUT That lead me to this page: https://xcp-ng.org/forum/topic/10799/backup-timeout-error I moved the XO machine onto the same subnet as XCP, leaving the storage behind in a different network. This fixed the issue, at least on commit e492b ... I have not yet tried it on the new release... however I am pretty confident it will be successful. If I'm honest, I think this is a tuning issue between XO and XCP. XO is now mounting an NFS share across this subnet boundary and that mount is not having any sort of performance issue, but for some reason XO times out transferring the same data from dom0? That seems off to me. It's not a probem moving XO to the other subnet, so I've done that, but maybe this deserves a look in the future.

Hi @jedimarcus, FYI, VIF creation is possible via the REST API POST /rest/v0/vifs

Because it works already better than the GO tool from Citrix… There's no urgent fix to do, I personally use it in my production since it's available. It's just less a priority for extra features because it's already ultra stable. Right now, we choose to work in priority on XCP-ng 9.0 than the Rust tools, we can't do everything at once yet.

@simonp said: @acebmxer Hi, Thanks to your help we were able to identify an issue with Redis that we think is the source of the v6 dashboard loading issue. Could you try and checkout the fix_redis_encryption_issue branch, rebuild xo and restart ? This should solve the 401 issues. Switched back to Master branch and made some changes to my install script. add diagnostics for missing XO 6 web UI build artifacts Plain bash [[ -f ]] fails silently on unreadable paths owned by SERVICE_USER, causing false-positive missing-artifact warnings. Switch all file/dir tests and grep calls to use sudo. SUCCESS] Xen Orchestra built successfully [INFO] Build verification passed: dist — all JS chunks present. [INFO] Build verification passed: dist — all JS chunks present. [INFO] Creating systemd service... [SUCCESS] Systemd service created and enabled [INFO] Configuring sudo for xo-service (mount/umount/findmnt)... [SUCCESS] Sudo configured for xo-service (mount, umount, findmnt) [INFO] Applying security hardening... [INFO] Starting xo-server service... [INFO] Waiting for Xen Orchestra to become ready (up to 60s)... [INFO] Not ready yet (attempt 1/10), retrying in 6s... [SUCCESS] Xen Orchestra is ready (HTTPS on port 443) [SUCCESS] Update completed successfully! [INFO] New commit: 0f29421627c7 v6 Dashboard still loading correctly. Thank you for the fix.

@abudef An overhaul of the guest agent is coming. We're considering adding some kind of update notifications as part of that overhaul, but it'll take some time to suss out the details. Autoupdating the Xen drivers is potentially disruptive and I'd prefer avoiding outages arising from an update coming at a bad time.