As it's a recently introduced bug, it will probably be fixed very soon. Got 'failure' on my weekly batch of backups during the night (4 machines using 'sequence'). This is real backups (but deltas) going to external storage.

"Global status: failure", but still transfers to storage seems to go through:

{
  "data": {
    "mode": "delta",
    "reportWhen": "failure"
  },
  "id": "1773627675367",
  "jobId": "b0f7dd0c-07c9-4cd8-938b-f519b0961b8d",
  "jobName": "ubu-01",
  "message": "backup",
  "scheduleId": "2e16be52-fc45-45d3-b73b-965d83235fa7",
  "start": 1773627675367,
  "status": "failure",
  "infos": [
    {
      "data": {
        "vms": [
          "31788a46-9fb1-3532-36b4-d9ad90c7d310"
        ]
      },
      "message": "vms"
    }
  ],
  "tasks": [
    {
      "data": {
        "type": "VM",
        "id": "31788a46-9fb1-3532-36b4-d9ad90c7d310",
        "name_label": "ubu-01"
      },
      "id": "1773627954874",
      "message": "backup VM",
      "start": 1773627954874,
      "status": "failure",
      "tasks": [
        {
          "id": "1773627954887",
          "message": "clean-vm",
          "start": 1773627954887,
          "status": "failure",
          "warnings": [
            {
              "data": {
                "path": "/xo-vm-backups/31788a46-9fb1-3532-36b4-d9ad90c7d310/vdis/b0f7dd0c-07c9-4cd8-938b-f519b0961b8d/35e6144b-5e78-4ae7-816f-abf21e73aeda/data/6d9d6dca-0803-4cc9-8e79-e049203d702e.vhd"
              },
              "message": "no alias references VHD"
            }
          ],
          "end": 1773627980060,
          "result": {
            "$fault": "server",
            "$metadata": {
              "httpStatusCode": 500,
              "requestId": "12284EA595C10B99",
              "extendedRequestId": "MTIyODRFQTU5NUMxMEI5OTEyMjg0RUE1OTVDMTBCOTkxMjI4NEVBNTk1QzEwQjk5MTIyODRFQTU5NUMxMEI5OQ==",
              "attempts": 3,
              "totalRetryDelay": 200
            },
            "name": "InternalError",
            "Code": "InternalError",
            "message": "Internal Error",
            "stack": "InternalError: Internal Error\n    at ProtocolLib.getErrorSchemaOrThrowBaseException (/opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/core/dist-cjs/submodules/protocols/index.js:69:67)\n    at AwsRestXmlProtocol.handleError (/opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/core/dist-cjs/submodules/protocols/index.js:1801:65)\n    at AwsRestXmlProtocol.deserializeResponse (/opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@smithy/core/dist-cjs/submodules/protocols/index.js:309:24)\n    at process.processTicksAndRejections (node:internal/process/task_queues:103:5)\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@smithy/core/dist-cjs/submodules/schema/index.js:26:24\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/middleware-sdk-s3/dist-cjs/index.js:386:20\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@smithy/middleware-retry/dist-cjs/index.js:254:46\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/middleware-sdk-s3/dist-cjs/index.js:63:28\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/middleware-sdk-s3/dist-cjs/index.js:90:20\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/middleware-logger/dist-cjs/index.js:5:26"
          }
        },
        {
          "id": "1773627983950",
          "message": "snapshot",
          "start": 1773627983950,
          "status": "success",
          "end": 1773627992689,
          "result": "08492698-4a00-4412-4a22-ad1da6114206"
        },
        {
          "data": {
            "id": "c4e665e9-68c0-4824-b616-8e397350d44d",
            "isFull": false,
            "type": "remote"
          },
          "id": "1773627992689:0",
          "message": "export",
          "start": 1773627992689,
          "status": "failure",
          "tasks": [
            {
              "id": "1773627998066",
              "message": "transfer",
              "start": 1773627998066,
              "status": "success",
              "end": 1773629436434,
              "result": {
                "size": 31975276544
              }
            },
            {
              "id": "1773629446409",
              "message": "clean-vm",
              "start": 1773629446409,
              "status": "failure",
              "warnings": [
                {
                  "data": {
                    "path": "/xo-vm-backups/31788a46-9fb1-3532-36b4-d9ad90c7d310/vdis/b0f7dd0c-07c9-4cd8-938b-f519b0961b8d/35e6144b-5e78-4ae7-816f-abf21e73aeda/data/6d9d6dca-0803-4cc9-8e79-e049203d702e.vhd"
                  },
                  "message": "no alias references VHD"
                }
              ],
              "end": 1773629506113,
              "result": {
                "$fault": "server",
                "$metadata": {
                  "httpStatusCode": 500,
                  "requestId": "12284EA595C154A2",
                  "extendedRequestId": "MTIyODRFQTU5NUMxNTRBMjEyMjg0RUE1OTVDMTU0QTIxMjI4NEVBNTk1QzE1NEEyMTIyODRFQTU5NUMxNTRBMg==",
                  "attempts": 3,
                  "totalRetryDelay": 144
                },
                "name": "InternalError",
                "Code": "InternalError",
                "message": "Internal Error",
                "stack": "InternalError: Internal Error\n    at ProtocolLib.getErrorSchemaOrThrowBaseException (/opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/core/dist-cjs/submodules/protocols/index.js:69:67)\n    at AwsRestXmlProtocol.handleError (/opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/core/dist-cjs/submodules/protocols/index.js:1801:65)\n    at AwsRestXmlProtocol.deserializeResponse (/opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@smithy/core/dist-cjs/submodules/protocols/index.js:309:24)\n    at process.processTicksAndRejections (node:internal/process/task_queues:103:5)\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@smithy/core/dist-cjs/submodules/schema/index.js:26:24\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/middleware-sdk-s3/dist-cjs/index.js:386:20\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@smithy/middleware-retry/dist-cjs/index.js:254:46\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/middleware-sdk-s3/dist-cjs/index.js:63:28\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/middleware-sdk-s3/dist-cjs/index.js:90:20\n    at async /opt/xo/xo-builds/xen-orchestra-202603131938/node_modules/@aws-sdk/middleware-logger/dist-cjs/index.js:5:26"
              }
            }
          ],
          "end": 1773629506114
        }
      ],
      "end": 1773629506114
    }
  ],
  "end": 1773629506114
}

This did not happen with the previous version (but that is more than a month old, so I'm not going back yet)

I thought I solved it.. but now the problem is back again:

Yesterday, 14 March, I did the following:

• deleted the snapshots on the running Deb12-XO machine, so it was clean
• deleted the clones of the machine
• ran the backup job maually - with success (transferred about 30G to the other host)
  (still on the "old" XO version)

Checked the destination host - no clone (backup) of the VM found.

• manually created two (full, not quick) clones of the VM so it won't be lost of anything goes sideways
• updated XO to the latest (2aff8)
• let it do the relication according to the schedule
• 21:00 replication success

Next morning (15 Mar) 09:00 replication also ran without any issues - at least according to the log.

• no additional copy of the VM on the destination host (retention is set to 2, so I should have one 21:00 and room for the 09:00 too)

Evening replication, 21:00, failed. Got that same error message as before:

VM Backup report

Global status : failure

Job ID: 883e2ee8-00c8-43f8-9ecd-9f9aa7aa01d1
Run ID: 1773604800005
Mode: delta
Start time: Sunday, March 15th 2026, 9:00:00 pm
End time: Sunday, March 15th 2026, 9:00:13 pm
Duration: a few seconds
Successes: 0 / 1
Transfer size: 126 MiB

1 Failure
Deb12-XO
Debian 12 XO self-install

Pool id: 4cc74549-71c3-31d5-f204-7106e90acd1e
UUID: 30829107-2a1b-6b20-a08a-f2c1e612b2ee
Start time: Sunday, March 15th 2026, 9:00:02 pm
End time: Sunday, March 15th 2026, 9:00:13 pm
Duration: a few seconds
Error: _removeUnusedSnapshots don't handle vdi related to multiple VMs Deb12-XO - Deb12-XO - (20260315T080004Z) and [XO Backup Deb12-XO] Deb12-XO

=
I notice the name of the snapshot seems odd:
[XO Backup Deb12-XO] Deb12-XO - Deb12-XO

Maybe just a new naming convention, but I found the old one better (for my Admin VM):
Admin Ubuntu 24 - Admin Ubuntu 24 - (20260201T125508Z)
Admin Ubuntu 24 - Admin Ubuntu 24 - (20260208T125508Z)
(I assume the double "Admin Ubuntu 24" is because the backup job name is the same as the machine name)

Yesterday, I installed the patches on my three hosts and rebooted them, directly followed by updating XO on my Debian machine to the latest (2cd5b at that time).
Since then, both the evening-replication (21:00) of my Deb12-XO host failed, as well as the morning-replication (09:00). This one has never failed before and is (was) being replicated to another host on the same network.

The mail-report says:
Debian 12 XO self-install

Pool id: 4cc74549-71c3-31d5-f204-7106e90acd1e
UUID: 30829107-2a1b-6b20-a08a-f2c1e612b2ee
Start time: Friday, March 13th 2026, 9:00:01 am
End time: Friday, March 13th 2026, 9:00:28 am
Duration: a few seconds
Error: _removeUnusedSnapshots don't handle vdi related to multiple VMs Deb12-XO - Deb12-XO - (20260312T200004Z) and [XO Backup Deb12-XO] Deb12-XO

As my XO-installation is outdated, I will update again and let it retry the replication without any other changes.

Also, this is probably nothing else than an annoying incorrect error message from microsoft:

What I did: followed the link in "About" to the current commit, went back to main, and clicked the link to all commits to see what I've missed (4 commits after I update XO)

@florent said in Continuous Replication jobs creates full backups every time since 2025-09-06 (xo from source):

@Andrew @peo
are you using purge snapshot data ?
In both case, can you try disabling it and disabling CBT on the relevant VMs ?

Yes, I was using CBT + purge snapshots, but that might not have been the reason for the sluggish transfer speeds with the later versions of XO.

I discovered that the SSD on my destination host were going bad, a write of a /dev/null-filled test file (1GB then 5GB) on the device started at expected 450MB/s, but slowed down to less than 10MB/s. Found a bunch of unexpected errors (because the disk was more or less new) in the logs by dmesg.
Doing the replication to another host made it fast even when transferred in full.
CBT+delete = still "Backup fell back to a full" (this was the third since my XO update)
CBT w/o delete = first backup=full transfer (4 min) and garbage collection (a few more minutes), second=delta transfer (a few seconds backup time)

I'm currently testing the "fixed" version. At the time I ran the replications the first time, I expected and accepted it doing new "first" full backups/transfers, but even this small, singe-disk VM (the one for my XO) is still doing full transfers:

This simple operation previously taking 2-5 minutes now takes 44 minutes:

Compared to the previous "normal" backup time:

The same goes for "Admin Ubuntu 24", single but slightly larger disk (50GB) which yesterday took 4 hours (initial "new" "first" backup, so I don't know if it still takes that time)

Too bad it becomes that unexplainable slow when it has to fall back to a full backup:

The first (full) backup was 10x faster:

@olivierlambert said in Continuous Replication jobs creates full backups every time since 2025-09-06 (xo from source):

No, no confirmation so far, that's why we need more to investigate

Great (or maybe not) news.. At least on my system this is very easy to replicate.. On a tiny test machine that only have had a normal backup before, first time doing replication copy (to H2 SSD) it sends it as full as expected. Just did some simple operations on the machine (like apt update, no upgrade), then retried:

@olivierlambert Has the problem been confirmed ? I can try to pinpoint where the always-full replications were introduced, but more time efficient to do it on a machine that is fast do replicate, not the one that now takes 2.5 hours (a few minutes for the diff before it borked starting at the backup made 6 Sept)

@olivierlambert said in Continuous Replication jobs creates full backups every time since 2025-09-06 (xo from source):

git bissect

That might be quite a bunch of commits in between the working one and when I discovered the problems (I actually let it do it's thing a couple of days, quickly filling up the backup drive)
I keep only the current and the previous build of XO, so I only know it's somewhere between Aug 16 (from the 'lastlog' to find out when I was logged in) and late Sep 5.

Anyone else experiencing the same problem, or is it just a problem of my imagination?

Recap:

Since 2025-09-06, all Continuous Replication jobs are creating full backups instead of incrementals.

Environment: XO from source, updated to commit c2144 (2 commits behind at the time of test).

Replication target: a standalone host that is part of the pool, on the same local network, with local SSD storage.

Logs and status screenshots were attached in my first post.

What I’ve done so far:
2025-09-11

• Updated Xen Orchestra to the latest commits (as of 2025-09-11).
• Restarted the XO VM and the source VM after update.

2025-09-12:

• Applied pool patches as they became available.
• Installed host updates and rebooted hosts.
• Restarted the source and target hosts (since all hosts were restarted).
• Verified behavior again today → still a full backup for the “Admin Ubuntu 24” VM.

Observation:
The issue began exactly after the 2025-09-05 updates (which included a set of host patches).
Since then, every daily replication runs as a full.