VDI not showing in XO 5 from Source.

[Pilow]

@Gheppy if you can have downtime snapshot/revert works

[limezest]

I'm seeing this same problem in my lab, and I've found a symptom that I'm calling "VDI super-parents"

There is a VDI metadata field called "snapshots:" if your VM has snapshots, this field will be populated with a list of the snapshot VDI UUIDs.
If your VM has no snapshots, this field will be empty.
If your VM is a super-parent, it will have a list of VDI UUIDs that are actually the primary disk for other, unrelated VMs. In this case, XO5 will hide those VDIs from the list of disks because they've been determined to be snapshots.

As far as I can tell, XO5 has two methods for figuring out which VDI are snapshots:

1. It looks at the "is-a-snapshot:" field
2. It builds a map of parents and children from the "snapshot-of:" and "snapshots:" metadata fields (as @pilow found)

XO6 seems to only look at the "is-a-snapshot:" metadata field.

Now here's the question: why is this happening? I only started seeing this behavior after installing XO6 preview.
Maybe it was due to an incomplete backup operation?
I have a bunch of VMs which are clones of a template.
I use iSCSI SRs.

Doing a xe vdi-copy to a new SR collapses the snapshot chain and makes new VDI metadata, and then I did a vbd unplug and destroy, then connected the copied VDI to a new VBD. This fixed the problem for the first test VM that I messed with.

[olivierlambert]

@anthoineb have we found a possible explanation?

[wilsonqanda]

Hello All,

This issue seem to completely go away on a older branch/tag if i build it from below for XO:
xo-lite-v0.17.0

So the issue I would think is coming from the newer version of XO. Not sure best way to test this. So I am going back to an older commit.

If anyone has any suggestion I can try helping as its an annoying issue.

[andrewperry]

We have been quietly suffering without the time to try and resolve it for the past couple of months.

I have now spent the day trying to resolve it in our environment, as we have one SR having this problem with some hundreds! of vdi.

I am having the same problem whether running the docker container version of XO CE or the local install on a VM we've been using for ages.

It seems that the api call from the VDIs tab in v6 (Disks in v5) may be triggering a call to the wrong url, without the /rest/v0 prefix:

sudo journalctl -u xo-server -n 300 --no-pager

2026-02-26T06:01:57.169Z xo:rest-api:error-handler INFO [GET] /vms/[[UUID]]/vdis (404)

I had the same experience as some others for a while, a couple of months ago, where it would not show up in the v5 UI but was showing in v6, but very quickly after that it stopped working in either.

I know that these are VDIs with a snapshot in the chain, for example a parent VDI that may have two snapshots from it.

I had thought the issue may have something to do with https://github.com/vatesfr/xen-orchestra/pull/9381, as it was around this time that I saw the problem in v6 - but I see that this topic was started just before Christmas so there must have been something else too, perhaps that is when it emerged in v5 and this later patch then surfaced it in v6.

If I run curl with the /rest/v0 prefix to the url I don't get the 404.

I hope this helps to track it down!

MathieuRA opened this pull request in vatesfr/xen-orchestra

closed fix(rest-api): fix getVmVdis and enhance the type #9381

[florent]

@andrewperry hi this is an identified issue on xapi / storage side
this commit is making it visible .

Pinging @anthoineb here for more info

[andrewperry]

@florent Thanks, if there is something I need to do to coalesce the vdis to avoid disaster, that would be good to understand. I had been thinking it was just an XO issue that would not affect running vms and their vdis.

[bogikornel]

@florent The following error occurred:

Mar 16 18:38:10 XOA xo-server[4001]: 2026-03-16T17:38:10. 246Z xo:rest-api:error-handler INFO [GET] /vms/0691be81-7ce9-7dba-9387-5620f8e0c52f/vdis (404)

XO version: Master, commit 15917
xcp-ng version: 8.3 with the latest updates.

What’s interesting is that there are two xcp-ng servers, and the problem only occurs on one of them.

[anthoineb]

@andrewperry Hi, we are working on 2 thinks:

1. a proper fix under development to avoid new issue where snapshot-of field is garbage.
2. a script to fix the wrongly set snapshot-of already present on affected pools.
   Both are necessary and we hope we can release the script soon to at least workaround if the issue happen again before we release the fix.

[Pilow]

@anthoineb wow great news ! still impacted by this issue