@david.bigagli
Hi Oliver,
thanks to your suggestion I solved the problem.

Thanks again.

@olivierlambert wow, thanks for this trick.
I'll try it and let you know the result

@olivierlambert No. The backup takes more than 24 hours.

Good morning,
I have a problem with the backup of a really large vm.
The vm has 4 disks with the following sizes:

• 200GB
• 2TB
• 1.5TB
• 1TB

The VM runs on an XCP-NG 8.2.1 with ext storage.
I am using a Xen Orchestra Community (Xen Orchestra, commit f8303, Master, commit ad8f8)
The configured backup is of type Delta to a nas as a destination.

After many hours of execution, the backup fails both using nfs and smb.

At a certain point I notice that the export/inport tasks disappear but apparently it seems that the backup continues: the space occupied on the destination continues to grow and the job status remains in running.

After a few more hours the job fails.

The backup logs are as follows.

{
  "data": {
    "mode": "delta",
    "reportWhen": "always"
  },
  "id": "1742229954295",
  "jobId": "86618265-dc14-434c-aaf3-5e8376623fe4",
  "jobName": "delta",
  "message": "backup",
  "scheduleId": "52158eff-4c17-492e-ae95-f11d7de27c4b",
  "start": 1742229954295,
  "status": "failure",
  "infos": [
    {
      "data": {
        "vms": [
          "db412111-605b-bb13-20cb-fe45ab767afc",
          "96080cea-76c6-2232-b453-c801920a1d9f",
          "b86e0a24-9836-3438-057d-cac947298fdf",
          "8a896312-f4c1-a9a9-f883-db036ff9d506",
          "adcb3b3f-16d2-3cbb-d905-5ab6e3fd43e7",
          "0ebe42ae-6d0a-ba9b-a8c1-64e686e71f62",
          "1e84c1b6-ebe9-5a4e-3b5b-9013c286caa7"
        ]
      },
      "message": "vms"
    }
  ],
  "tasks": [
    {
      "data": {
        "type": "VM",
        "id": "db412111-605b-bb13-20cb-fe45ab767afc",
        "name_label": "FileSrv2022"
      },
      "id": "1742229955380",
      "message": "backup VM",
      "start": 1742229955380,
      "status": "failure",
      "tasks": [
        {
          "id": "1742229955411",
          "message": "clean-vm",
          "start": 1742229955411,
          "status": "success",
          "end": 1742229955415,
          "result": {
            "merge": false
          }
        },
        {
          "id": "1742229955580",
          "message": "snapshot",
          "start": 1742229955580,
          "status": "success",
          "end": 1742229969690,
          "result": "265d070b-9a68-bb99-3426-e2d8800ffca3"
        },
        {
          "data": {
            "id": "f7b4e6f0-94bb-45cf-8c87-e046848e564d",
            "isFull": true,
            "type": "remote"
          },
          "id": "1742229969691",
          "message": "export",
          "start": 1742229969691,
          "status": "failure",
          "tasks": [
            {
              "id": "1742229971026",
              "message": "transfer",
              "start": 1742229971026,
              "status": "failure",
              "end": 1742361517276,
              "result": {
                "generatedMessage": false,
                "code": "ERR_ASSERTION",
                "actual": false,
                "expected": true,
                "operator": "==",
                "message": "footer1 !== footer2",
                "name": "AssertionError",
                "stack": "AssertionError [ERR_ASSERTION]: footer1 !== footer2\n    at VhdFile.readHeaderAndFooter (/opt/xo/xo-builds/xen-orchestra-202412170947/packages/vhd-lib/Vhd/VhdFile.js:195:7)\n    at async VhdFile.open (/opt/xo/xo-builds/xen-orchestra-202412170947/packages/vhd-lib/Vhd/VhdFile.js:95:7)\n    at async openVhd (/opt/xo/xo-builds/xen-orchestra-202412170947/packages/vhd-lib/openVhd.js:15:14)\n    at async Promise.all (index 0)\n    at async checkVhd (file:///opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/backups/_runners/_writers/_checkVhd.mjs:5:3)\n    at async NfsHandler._outputStream (/opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/fs/dist/abstract.js:558:9)\n    at async NfsHandler.outputStream (/opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/fs/dist/abstract.js:180:5)\n    at async RemoteAdapter.outputStream (file:///opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/backups/RemoteAdapter.mjs:705:5)\n    at async asyncEach.concurrency (file:///opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/backups/_runners/_writers/IncrementalRemoteWriter.mjs:236:39)"
              }
            }
          ],
          "end": 1742361517279,
          "result": {
            "generatedMessage": false,
            "code": "ERR_ASSERTION",
            "actual": false,
            "expected": true,
            "operator": "==",
            "message": "footer1 !== footer2",
            "name": "AssertionError",
            "stack": "AssertionError [ERR_ASSERTION]: footer1 !== footer2\n    at VhdFile.readHeaderAndFooter (/opt/xo/xo-builds/xen-orchestra-202412170947/packages/vhd-lib/Vhd/VhdFile.js:195:7)\n    at async VhdFile.open (/opt/xo/xo-builds/xen-orchestra-202412170947/packages/vhd-lib/Vhd/VhdFile.js:95:7)\n    at async openVhd (/opt/xo/xo-builds/xen-orchestra-202412170947/packages/vhd-lib/openVhd.js:15:14)\n    at async Promise.all (index 0)\n    at async checkVhd (file:///opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/backups/_runners/_writers/_checkVhd.mjs:5:3)\n    at async NfsHandler._outputStream (/opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/fs/dist/abstract.js:558:9)\n    at async NfsHandler.outputStream (/opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/fs/dist/abstract.js:180:5)\n    at async RemoteAdapter.outputStream (file:///opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/backups/RemoteAdapter.mjs:705:5)\n    at async asyncEach.concurrency (file:///opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/backups/_runners/_writers/IncrementalRemoteWriter.mjs:236:39)"
          }
        }
      ],
      "end": 1742361517723,
      "result": {
        "generatedMessage": false,
        "code": "ERR_ASSERTION",
        "actual": false,
        "expected": true,
        "operator": "==",
        "message": "footer1 !== footer2",
        "name": "AssertionError",
        "stack": "AssertionError [ERR_ASSERTION]: footer1 !== footer2\n    at VhdFile.readHeaderAndFooter (/opt/xo/xo-builds/xen-orchestra-202412170947/packages/vhd-lib/Vhd/VhdFile.js:195:7)\n    at async VhdFile.open (/opt/xo/xo-builds/xen-orchestra-202412170947/packages/vhd-lib/Vhd/VhdFile.js:95:7)\n    at async openVhd (/opt/xo/xo-builds/xen-orchestra-202412170947/packages/vhd-lib/openVhd.js:15:14)\n    at async Promise.all (index 0)\n    at async checkVhd (file:///opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/backups/_runners/_writers/_checkVhd.mjs:5:3)\n    at async NfsHandler._outputStream (/opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/fs/dist/abstract.js:558:9)\n    at async NfsHandler.outputStream (/opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/fs/dist/abstract.js:180:5)\n    at async RemoteAdapter.outputStream (file:///opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/backups/RemoteAdapter.mjs:705:5)\n    at async asyncEach.concurrency (file:///opt/xo/xo-builds/xen-orchestra-202412170947/@xen-orchestra/backups/_runners/_writers/IncrementalRemoteWriter.mjs:236:39)"
      }
    },
    {
      "data": {
        "type": "VM",
        "id": "96080cea-76c6-2232-b453-c801920a1d9f",
        "name_label": "TEW12DC1"
      },
      "id": "1742229955382",
      "message": "backup VM",
      "start": 1742229955382,
      "status": "success",
      "tasks": [
        {
          "id": "1742229955412",
          "message": "clean-vm",
          "start": 1742229955412,
          "status": "success",
          "end": 1742229955417,
          "result": {
            "merge": false
          }
        },
        {
          "id": "1742229955581",
          "message": "snapshot",
          "start": 1742229955581,
          "status": "success",
          "end": 1742229956614,
          "result": "ab4d40c7-2809-2833-1594-ccef0a746f75"
        },
        {
          "data": {
            "id": "f7b4e6f0-94bb-45cf-8c87-e046848e564d",
            "isFull": true,
            "type": "remote"
          },
          "id": "1742229956615",
          "message": "export",
          "start": 1742229956615,
          "status": "success",
          "tasks": [
            {
              "id": "1742229957191",
              "message": "transfer",
              "start": 1742229957191,
              "status": "success",
              "end": 1742243763381,
              "result": {
                "size": 72084292096
              }
            },
            {
              "id": "1742243764544",
              "message": "clean-vm",
              "start": 1742243764544,
              "status": "success",
              "end": 1742243765209,
              "result": {
                "merge": false
              }
            }
          ],
          "end": 1742243765303
        }
      ],
      "end": 1742243765304
    },
    {
      "data": {
        "type": "VM",
        "id": "b86e0a24-9836-3438-057d-cac947298fdf",
        "name_label": "TEW19DC2"
      },
      "id": "1742243765309",
      "message": "backup VM",
      "start": 1742243765309,
      "status": "success",
      "tasks": [
        {
          "id": "1742243765443",
          "message": "clean-vm",
          "start": 1742243765443,
          "status": "success",
          "end": 1742243765621,
          "result": {
            "merge": false
          }
        },
        {
          "id": "1742243765679",
          "message": "snapshot",
          "start": 1742243765679,
          "status": "success",
          "end": 1742243766542,
          "result": "2fee117e-3232-5e4a-6b10-09bff6b485f6"
        },
        {
          "data": {
            "id": "f7b4e6f0-94bb-45cf-8c87-e046848e564d",
            "isFull": true,
            "type": "remote"
          },
          "id": "1742243766542:0",
          "message": "export",
          "start": 1742243766542,
          "status": "success",
          "tasks": [
            {
              "id": "1742243767274",
              "message": "transfer",
              "start": 1742243767274,
              "status": "success",
              "end": 1742251099064,
              "result": {
                "size": 45571916800
              }
            },
            {
              "id": "1742251100383",
              "message": "clean-vm",
              "start": 1742251100383,
              "status": "success",
              "end": 1742251100985,
              "result": {
                "merge": false
              }
            }
          ],
          "end": 1742251101051
        }
      ],
      "end": 1742251101051
    },
    {
      "data": {
        "type": "VM",
        "id": "8a896312-f4c1-a9a9-f883-db036ff9d506",
        "name_label": "centos"
      },
      "id": "1742251101069",
      "message": "backup VM",
      "start": 1742251101069,
      "status": "success",
      "tasks": [
        {
          "id": "1742251101196",
          "message": "clean-vm",
          "start": 1742251101196,
          "status": "success",
          "end": 1742251101402,
          "result": {
            "merge": false
          }
        },
        {
          "id": "1742251101460",
          "message": "snapshot",
          "start": 1742251101460,
          "status": "success",
          "end": 1742251102307,
          "result": "698975a3-2709-8ee8-2d73-351757be4d37"
        },
        {
          "data": {
            "id": "f7b4e6f0-94bb-45cf-8c87-e046848e564d",
            "isFull": true,
            "type": "remote"
          },
          "id": "1742251102307:0",
          "message": "export",
          "start": 1742251102307,
          "status": "success",
          "tasks": [
            {
              "id": "1742251103003",
              "message": "transfer",
              "start": 1742251103003,
              "status": "success",
              "end": 1742251388494,
              "result": {
                "size": 1451618816
              }
            },
            {
              "id": "1742251389453",
              "message": "clean-vm",
              "start": 1742251389453,
              "status": "success",
              "end": 1742251390163,
              "result": {
                "merge": false
              }
            }
          ],
          "end": 1742251390206
        }
      ],
      "end": 1742251390206
    },
    {
      "data": {
        "type": "VM",
        "id": "adcb3b3f-16d2-3cbb-d905-5ab6e3fd43e7",
        "name_label": "centos7"
      },
      "id": "1742251390211",
      "message": "backup VM",
      "start": 1742251390211,
      "status": "success",
      "tasks": [
        {
          "id": "1742251390325",
          "message": "clean-vm",
          "start": 1742251390325,
          "status": "success",
          "end": 1742251390527,
          "result": {
            "merge": false
          }
        },
        {
          "id": "1742251390585",
          "message": "snapshot",
          "start": 1742251390585,
          "status": "success",
          "end": 1742251391424,
          "result": "0544df94-804c-e8c7-8b05-6e84f95ebf00"
        },
        {
          "data": {
            "id": "f7b4e6f0-94bb-45cf-8c87-e046848e564d",
            "isFull": true,
            "type": "remote"
          },
          "id": "1742251391424:0",
          "message": "export",
          "start": 1742251391424,
          "status": "success",
          "tasks": [
            {
              "id": "1742251392106",
              "message": "transfer",
              "start": 1742251392106,
              "status": "success",
              "end": 1742262159532,
              "result": {
                "size": 72560461824
              }
            },
            {
              "id": "1742262160630",
              "message": "clean-vm",
              "start": 1742262160630,
              "status": "success",
              "end": 1742262161235,
              "result": {
                "merge": false
              }
            }
          ],
          "end": 1742262161294
        }
      ],
      "end": 1742262161294
    },
    {
      "data": {
        "type": "VM",
        "id": "0ebe42ae-6d0a-ba9b-a8c1-64e686e71f62",
        "name_label": "srvdom01"
      },
      "id": "1742262161300",
      "message": "backup VM",
      "start": 1742262161300,
      "status": "success",
      "tasks": [
        {
          "id": "1742262161426",
          "message": "clean-vm",
          "start": 1742262161426,
          "status": "success",
          "end": 1742262161577,
          "result": {
            "merge": false
          }
        },
        {
          "id": "1742262161639",
          "message": "snapshot",
          "start": 1742262161639,
          "status": "success",
          "end": 1742262162905,
          "result": "abf05fd8-8934-cc51-61f6-e22fecb36c38"
        },
        {
          "data": {
            "id": "f7b4e6f0-94bb-45cf-8c87-e046848e564d",
            "isFull": true,
            "type": "remote"
          },
          "id": "1742262162906",
          "message": "export",
          "start": 1742262162906,
          "status": "success",
          "tasks": [
            {
              "id": "1742262163607",
              "message": "transfer",
              "start": 1742262163607,
              "status": "success",
              "end": 1742273509362,
              "result": {
                "size": 70087459328
              }
            },
            {
              "id": "1742273510399",
              "message": "clean-vm",
              "start": 1742273510399,
              "status": "success",
              "end": 1742273511063,
              "result": {
                "merge": false
              }
            }
          ],
          "end": 1742273511150
        }
      ],
      "end": 1742273511151
    },
    {
      "data": {
        "type": "VM",
        "id": "1e84c1b6-ebe9-5a4e-3b5b-9013c286caa7",
        "name_label": "xo-ce"
      },
      "id": "1742273511154",
      "message": "backup VM",
      "start": 1742273511154,
      "status": "success",
      "tasks": [
        {
          "id": "1742273511356",
          "message": "clean-vm",
          "start": 1742273511356,
          "status": "success",
          "end": 1742273511553,
          "result": {
            "merge": false
          }
        },
        {
          "id": "1742273511612",
          "message": "snapshot",
          "start": 1742273511612,
          "status": "success",
          "end": 1742273512854,
          "result": "aa14e880-1171-0d2e-3885-47ab8c791c67"
        },
        {
          "data": {
            "id": "f7b4e6f0-94bb-45cf-8c87-e046848e564d",
            "isFull": true,
            "type": "remote"
          },
          "id": "1742273512854:0",
          "message": "export",
          "start": 1742273512854,
          "status": "success",
          "tasks": [
            {
              "id": "1742273513493",
              "message": "transfer",
              "start": 1742273513493,
              "status": "success",
              "end": 1742274467330,
              "result": {
                "size": 6769184768
              }
            },
            {
              "id": "1742274468420",
              "message": "clean-vm",
              "start": 1742274468420,
              "status": "success",
              "end": 1742274469111,
              "result": {
                "merge": false
              }
            }
          ],
          "end": 1742274469153
        }
      ],
      "end": 1742274469153
    }
  ],
  "end": 1742361517723
}

Can anyone tell me what the problem might be.