So if i set VMs to Best-effort or disabled for HA i get not enough memory. @pkgw Do you have Twinstore configured and/or HA enabled? If no I will continue my issues at the twinstore post. If i set to restart i get this.... host.setMaintenanceMode { "id": "35233210-4e37-4703-9bf6-9e8a9c24df9f", "maintenance": true } { "code": "HA_OPERATION_WOULD_BREAK_FAILOVER_PLAN", "params": [], "call": { "duration": 5, "method": "host.disable", "params": [ "* session id *", "OpaqueRef:d9bd976f-445c-8244-1b56-879f446efc12" ] }, "message": "HA_OPERATION_WOULD_BREAK_FAILOVER_PLAN()", "name": "XapiError", "stack": "XapiError: HA_OPERATION_WOULD_BREAK_FAILOVER_PLAN() at XapiError.wrap (file:///opt/xen-orchestra/packages/xen-api/_XapiError.mjs:16:12) at file:///opt/xen-orchestra/packages/xen-api/transports/json-rpc.mjs:38:21 at runNextTicks (node:internal/process/task_queues:65:5) at processImmediate (node:internal/timers:472:9)" }

@poddingue Bug report filed as requested — https://github.com/xcp-ng/xcp/issues/825 — and tagging @Team-Storage per your suggestion. Full evidence bundle is attached to the issue (versions, sweep output, vhd-util vs xe comparison, SMlog). Summary of what I found: One correction to the mechanism, and I think it matters. The recap describes is-a-snapshot being flipped to true. On my system that isn't what's happening — is-a-snapshot is false on every affected VDI. The field being wrongly written is snapshot-of, which is getting populated on base disks that aren't snapshots at all. XO's disappearing-disks symptom is consistent with either (it filters on a non-empty snapshot-of), but if the storage team is hunting for a bad is-a-snapshot write, that may be the wrong field. Every affected VDI here looks like: is-a-snapshot: false <-- correct snapshot-of: <populated with an unrelated VDI's UUID> <-- wrong A VDI that is a snapshot of itself. The clearest single artifact: uuid: 806f7f42-083f-4a40-b3f1-0700d00bab5a name-label: WinSrv2022SHB_Disk1_Data is-a-snapshot: false snapshot-of: 806f7f42-083f-4a40-b3f1-0700d00bab5a <-- itself snapshot-time: 20260709T11:19:15Z sm-config: vhd-parent: c86e3247-... <-- bears no relation to the snapshot-of value No valid code path produces snapshot-of = self. Whatever writes this field isn't validating the target. It's still actively corrupting new VDIs — this is not just legacy damage. That self-referential VDI was created 2026-07-09, a week after my patch + reboot. Sweeps 9 days apart went from ~180 → 191 affected VDIs on one SR, and a fourth anchor UUID appeared that didn't exist in the first sweep. Newly created VHDs keep landing in the affected set. So "stop it happening again" is the urgent half of the two-part fix, at least in my case. The bogus targets cluster onto a tiny anchor set, and the anchors point at each other: Count Anchor 97 937c3945 (→ a893fdb4) 50 a893fdb4 (→ ea150883) 37 ea150883 7 806f7f42 (→ itself, new since Jul 9) That looks less like corrupted lineage and more like the field being filled from an incorrect/uninitialised source. On-disk VHDs are completely healthy. vhd-util check says valid, parent locators are consistent, GC reports no work. The two VDIs the DB calls parent/child are, on disk, siblings under a common parent. The corruption is purely in the XAPI database — which is good news for recoverability. The VDI_IN_USE is not a real lock. current-operations is empty, xe task-list is empty, no tapdisk holds it. VM.start fails because it's walking a snapshot relationship that doesn't exist on disk. Reproduces from xe on the pool master with XO entirely out of the path — which is why I filed against xcp-ng/xcp rather than the XO tracker. Versions: XCP-ng 8.3.0, xapi 26.1.11 (xapi-core-26.1.11-1.2), sm-3.2.12-17.9, sm-fairlock-3.2.12-17.9, blktap 3.55.5-9.1, build 20260618. I have not attempted to bulk-clear the fields — on-disk data is intact and I'd rather not do a mass write against the XAPI DB on a live SR without guidance. Backing store snapshotted as a safety net. Happy to run whatever diagnostics would help. And +1 to the hand-grenade feeling — the affected set growing on its own is the part that worries me. kismetgerald created this issue in xcp-ng/xcp open XAPI DB corruption: base VDIs mass-stamped with invalid `snapshot-of` (incl. a VDI that is a snapshot of *itself*), blocking `VM.start` with VDI_IN_USE — and still ongoing #825

Hello. Problem Solved. My case: i have a pool of many hypervisors with only local storage, no shared SR ( yes it's not recommanded, i stopped doing this and i'm currently migrating everything to pool with Shared storage ). Yesterday, i removed two hosts ( host 3 & host 4 ) whith local storages SR attached ( LVM ). In XCP-NG, i "forgot" Host 3 & host 4, the hosts from the pool, but it doesn't forge the associated SR ! But Live migrating a VM from host 1 to host 2 ( of the same pool ) bot with local SR, FAIL because there is no SR plugin attached of Local Storage 4 ( hosts 4 ) neither Local storage 3 ( host 3 ). So, i also forget theses 2 SRs and now it's ok. i don't understand why SR not connected to anyone can prevent migration about vm from other to other sr.

Hi @simonp The host was restarted regularly. After every update I restart the host and consequently all VMs running on it. The XOA VM is also running on that host. Regards, Marc

@poddingue My three hosts are all EDT, drift on mine is pretty small because I have a local NTP server with GNSS. So it could be a timezone issue and might be worth looking into.