CBT: the thread to centralize your feedback

flakpyro

@rtjdamen After testing with both single disk VMs and multi disk i am seeing it on both. However it is much more common on multi disk VMs.

rtjdamen

@flakpyro are u able to test it on iscsi?

flakpyro

@rtjdamen I dont not have any iscsi luns mapped to our hosts to test with. We went all in with NFS from iscsi as we moved from ESXi to XCP-NG.

rizaemet 0

After the CBT feature was added to the backup method, The error "VDI must be free or attached to exactly one VM" was occurring on our system. Today I upgraded XO to the e15f2a1 and tried taking full and delta backups with Continuous Replication. Now everything works fine.
NBD connection enabled, NBD+CBT backup enabled, XCP-ng 8.2, CR backup from FC storage to NFS storage.

olivierlambert

Great news! Other similar feedback in here?

rtjdamen

@olivierlambert can’t check, running on xoa.

olivierlambert

It will be available in 12 days then

rtjdamen

@olivierlambert indeed haha, most things work like a charm, some issues but i know florent is still working on them.

olivierlambert

Yes, as you can see in here, we are fixing most of the remaining issues to be ready on next week for our next release

flakpyro

So i have had good luck with NBD+CBT enabled for around the last week, however "Purge snapshot data when using CBT" causes me a number of issues unfortunately especially after a migration from one host to another with a shared SR as reported above. Hoping to see that fixed in the next release coming soon!

Recently I've discovered that it seems the coalesce process with "purge snapshot data" enabled does something our NFS storage array does not like. If a coalesce process with "Purge snapshot data when using CBT" enabled runs for too long of time the NFS server will start dropping connections. I have had this happen a few times last week and have not been able to explain it. Is the process quite different from the standard coalesce process? Trying to come up with something to explain why the array gets so angry!

I have a case open with our storage vendor and they pointed out that the client gets disconnected due to expired NFS leases when this happens. It might be a coincidence this happens during backup runs, if it continues to happen i plan to try NFS3 instead of NFS4.1 as well but something i thought i'd report!

Tristis Oris

i try to migrate VDIs to another storage. After 4 hours no one is migrated, new tasks run and close in loop.

olivierlambert

I think a fix is coming very soon in master by @florent

flakpyro

@olivierlambert

Sadly the latest XOA update does not seem to resolve the "falling back to base" issue for me which occurs after migrating a VM from one host to another. (Using a shared NFS3 SR)

olivierlambert

Can you bring the entire log please? We cannot reproduce the issue This should NOT happen if the VDI UUID is the same.

flakpyro

@olivierlambert For sure! Where is the log location on the XOA appliance? I'd be happy to provide it. I can also provide a support tunnel!

I can reproduce this on 2 separate pools (both using NFS3) so getting logs should be easy!

rtjdamen

I am testing the new release as well but we had some issue this week with one repository so i need to fix that as well. So far the jobs seem to process normally.

@olivierlambert or @florent what issues should be fixed by this release?

olivierlambert

@flakpyro Don't you have a small download button for the backup log to get the entire log?

flakpyro

@olivierlambert My bad i see the button to download the log now!

Here is the log: https://drive.google.com/file/d/1OO8Rs6pST-W0qplpVu-E5lafYFXzhJA2/view?usp=drive_link

SylvainB

Hi,

Same here, I updated XOA to 5.98 and I have this error

"can't create a stream from a metadata VDI, fall back to a base" on some VM

I have an active support contract.

Here the detailed log

{
      "data": {
        "type": "VM",
        "id": "96cfde06-61c0-0f3e-cf6d-f637d41cc8c6",
        "name_label": "blabla_VM"
      },
      "id": "1725081943938",
      "message": "backup VM",
      "start": 1725081943938,
      "status": "failure",
      "tasks": [
        {
          "id": "1725081943938:0",
          "message": "clean-vm",
          "start": 1725081943938,
          "status": "success",
          "end": 1725081944676,
          "result": {
            "merge": false
          }
        },
        {
          "id": "1725081944876",
          "message": "snapshot",
          "start": 1725081944876,
          "status": "success",
          "end": 1725081978972,
          "result": "46334bc0-cb3c-23f7-18e1-f25320a6c4b4"
        },
        {
          "data": {
            "id": "122ddf1f-090d-4c23-8c5e-fe095321f8b9",
            "isFull": false,
            "type": "remote"
          },
          "id": "1725081978972:0",
          "message": "export",
          "start": 1725081978972,
          "status": "success",
          "tasks": [
            {
              "id": "1725082089246",
              "message": "clean-vm",
              "start": 1725082089246,
              "status": "success",
              "end": 1725082089709,
              "result": {
                "merge": false
              }
            }
          ],
          "end": 1725082089719
        },
        {
          "data": {
            "id": "beee944b-e502-61d7-e03b-e1408f01db8c",
            "isFull": false,
            "name_label": "BLABLA_SR_HDD-01",
            "type": "SR"
          },
          "id": "1725081978972:1",
          "message": "export",
          "start": 1725081978972,
          "status": "pending"
        }
      ],
      "infos": [
        {
          "message": "will delete snapshot data"
        },
        {
          "data": {
            "vdiRef": "OpaqueRef:1b614f6b-0f69-47a1-a0cd-eee64007441d"
          },
          "message": "Snapshot data has been deleted"
        }
      ],
      "warnings": [
        {
          "data": {
            "error": {
              "code": "VDI_IN_USE",
              "params": [
                "OpaqueRef:989f7dd8-0b73-4a87-b249-6cfc660a90bb",
                "data_destroy"
              ],
              "call": {
                "method": "VDI.data_destroy",
                "params": [
                  "OpaqueRef:989f7dd8-0b73-4a87-b249-6cfc660a90bb"
                ]
              }
            },
            "vdiRef": "OpaqueRef:989f7dd8-0b73-4a87-b249-6cfc660a90bb"
          },
          "message": "Couldn't deleted snapshot data"
        }
      ],
      "end": 1725082089719,
      "result": {
        "message": "can't create a stream from a metadata VDI, fall back to a base ",
        "name": "Error",
        "stack": "Error: can't create a stream from a metadata VDI, fall back to a base \n    at Xapi.exportContent (file:///usr/local/lib/node_modules/xo-server/node_modules/@xen-orchestra/xapi/vdi.mjs:202:15)\n    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)\n    at async file:///usr/local/lib/node_modules/xo-server/node_modules/@xen-orchestra/backups/_incrementalVm.mjs:57:32\n    at async Promise.all (index 0)\n    at async cancelableMap (file:///usr/local/lib/node_modules/xo-server/node_modules/@xen-orchestra/backups/_cancelableMap.mjs:11:12)\n    at async exportIncrementalVm (file:///usr/local/lib/node_modules/xo-server/node_modules/@xen-orchestra/backups/_incrementalVm.mjs:26:3)\n    at async IncrementalXapiVmBackupRunner._copy (file:///usr/local/lib/node_modules/xo-server/node_modules/@xen-orchestra/backups/_runners/_vmRunners/IncrementalXapi.mjs:44:25)\n    at async IncrementalXapiVmBackupRunner.run (file:///usr/local/lib/node_modules/xo-server/node_modules/@xen-orchestra/backups/_runners/_vmRunners/_AbstractXapi.mjs:379:9)\n    at async file:///usr/local/lib/node_modules/xo-server/node_modules/@xen-orchestra/backups/_runners/VmsXapi.mjs:166:38"
      }
    },

rtjdamen

So far i did see this fall back to base error only once, it looks like it does finish correct in the retry action. I will keep an eye on this.