@Danp Yes later I did try and it restore the vm along side the original with the "_" a underscore appended to the end of the name of the vm. Original - Windows Server 2022. Restored - Windows Server 2022_

@olivierlambert Happy to hear that they are providing results to be looked at. If there is anything else I can provide, please don't hesitate to ask. And I'll do my very best to be helpfull

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

Trying to pull the last few posts together, because there is a pattern I keep staring at. Every failed run in @JB's screenshots lasts exactly 5 minutes while the successful ones finish in seconds, and @abudef's history going back to 23 June shows the same 5-minute wall. That reads to me like a fixed timeout firing rather than a merely slow transfer, though I could be wrong about which one. @christopher-petzel's syslog looks like a different animal, since assert(!this.paused) in undici's Parser.finish is xo-server crashing outright at job start while 13 other instances backed up fine the same minute. The only knob I can find written down is httpInactivityTimeout at https://docs.xen-orchestra.com/xo5/backup_troubleshooting#error-http-connection-has-timed-out, but that one sits on the XAPI GET path, and I do not know whether it touches pool metadata jobs at all. @florent, does the 5-minute signature change anything on your side?

Merci pour les précisions, elles écartent ma piste. Si vous reproduisez en BIOS comme en UEFI, le ticket #151 ne colle pas, d'autant qu'il parle de l'installeur Windows et pas d'Anaconda : je l'avais résumé un peu vite. La différence intéressante est peut-être RHEL 9 contre RHEL 10, puisque @AtaxyaNetwork a un build qui fonctionne en 10 avec cd_files et sans DHCP, et son test en 9 ce week-end devrait trancher. Sur cd_label = "OEMDRV", je n'ai trouvé ni issue ni PR dans le dépôt du plugin, donc ça n'existe visiblement pas encore : si ça vous va, ça ferait une demande propre à ouvrir sur https://github.com/vatesfr/packer-plugin-xenserver, en reprenant l'argument air-gapped que vous détaillez plus haut, qui est plus convaincant que ce que j'écrirais moi. Je ne connais pas assez le plugin pour dire si c'est simple à ajouter, donc je préfère ne rien promettre. Merci en tout cas de documenter tout précisément, ça servira sans doute bien au-delà de votre POC.

@acebmxer Thank you for your quick feedback.

Great, thanks for the feedback!

A remote is not the same thing as a SR. For a remote, it's simple: disconnect it (click on "Enabled" so it's disabled then), do whatever you need on the NFS server, re-enable.

@acebmxer all good and thank you again for sharing your discovery on the forums

@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.

@poddingue The other option would be to be able to offer a different default /etc/ssh/sshd_config option but that's embedded in the Linux OS. One other possibility would be to create a startup job that runs out of /etc/rc.local and has a script that makes the changes after-the-fact. Just a thought...

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

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

Actually, isn't XAPI 24.19.2 what is shipped with the original XCP-ng 8.3 release? If so, then you could just do this -- Reinstall XCP-ng on the new host Restore the pool metadata Patch the host

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.

All hosts are restarted with 9.2.18 loaded now. Will see what happens next. [15:56 ovbh-pprod-xen05 ~]# drbdadm --version DRBDADM_BUILDTAG=GIT-hash:\ 71c8bcff6ea77a022b272a7eba649a774251bac4\ build\ by\ @buildsystem\,\ 2025-11-03\ 10:21:36 DRBDADM_API_VERSION=2 DRBD_KERNEL_VERSION_CODE=0x090212 DRBD_KERNEL_VERSION=9.2.18 DRBDADM_VERSION_CODE=0x092100 DRBDADM_VERSION=9.33.0

Good news that it sorted itself out. Both changes went in at once and the next run came back clean on the ADDS VMs too, so I don't think there's anything left to pin down here, and I'd rather say that than invent an explanation after the fact. Your question about the snapshot modes was the useful thing to come out of this thread. I went looking, they genuinely aren't documented anywhere, and that's written up on our side now If the fall back to a full ever comes back on the ADDS VMs specifically, that would deserve its own thread with the SMlog output @tjkreidl asked for, since nobody got to look at that part.

@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 !