Backup fails with "Body Timeout Error", "all targets have failed, step: writer.run()"

christopher-petzel

@florent suggesting this looks like a network issue, I took a look at my XO's server's syslog and found the error when this occurs.

2026-07-31T00:10:00.428083-04:00 mis-26-svr xo-server[1298]: 2026-07-31T04:10:00.427Z xo:xo-server ERROR uncaught exception {
2026-07-31T00:10:00.428186-04:00 mis-26-svr xo-server[1298]:   error: AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:
2026-07-31T00:10:00.428262-04:00 mis-26-svr xo-server[1298]:
2026-07-31T00:10:00.428309-04:00 mis-26-svr xo-server[1298]:     assert(!this.paused)
2026-07-31T00:10:00.428341-04:00 mis-26-svr xo-server[1298]:
2026-07-31T00:10:00.428391-04:00 mis-26-svr xo-server[1298]:       at Parser.finish (/opt/xo/xo-builds/xen-orchestra-202607200851/node_modules/undici/lib/dispatcher/client-h1.js:302:5)
2026-07-31T00:10:00.428414-04:00 mis-26-svr xo-server[1298]:       at TLSSocket.<anonymous> (/opt/xo/xo-builds/xen-orchestra-202607200851/node_modules/undici/lib/dispatcher/client-h1.js:741:32)
2026-07-31T00:10:00.428434-04:00 mis-26-svr xo-server[1298]:       at TLSSocket.emit (node:events:521:24)
2026-07-31T00:10:00.428478-04:00 mis-26-svr xo-server[1298]:       at TLSSocket.patchedEmit [as emit] (/opt/xo/xo-builds/xen-orchestra-202607200851/@xen-orchestra/log/configure.js:52:17)
2026-07-31T00:10:00.428508-04:00 mis-26-svr xo-server[1298]:       at endReadableNT (node:internal/streams/readable:1729:12)
2026-07-31T00:10:00.428525-04:00 mis-26-svr xo-server[1298]:       at processTicksAndRejections (node:internal/process/task_queues:90:21) {
2026-07-31T00:10:00.428549-04:00 mis-26-svr xo-server[1298]:     generatedMessage: true,
2026-07-31T00:10:00.428567-04:00 mis-26-svr xo-server[1298]:     code: 'ERR_ASSERTION',
2026-07-31T00:10:00.428582-04:00 mis-26-svr xo-server[1298]:     actual: false,
2026-07-31T00:10:00.428599-04:00 mis-26-svr xo-server[1298]:     expected: true,
2026-07-31T00:10:00.428614-04:00 mis-26-svr xo-server[1298]:     operator: '==',
2026-07-31T00:10:00.428628-04:00 mis-26-svr xo-server[1298]:     diff: 'simple'
2026-07-31T00:10:00.428642-04:00 mis-26-svr xo-server[1298]:   }
2026-07-31T00:10:00.428659-04:00 mis-26-svr xo-server[1298]: }

So it looks like xo-server is dying, could it be the module undici that the problem here? Keep in mind that 13 other instances of xo-server performed the backup without a problem at the exact same time. Some days this never happens, some days it could be 4 instances of xo-server that die the same way in executing the backup.

I think it's also important to note that the instance of xo-server dying happens immediately upon the backup being started at 10 minutes after midnight. I would think that if the problem were the network itself, that there would be some timeout period before causing the xo-server instance to crash.

To answer a question asked of @jb , this is a local XCP-ng management network and there are no other backups occurring at 00:10.

poddingue

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?

bogikornel

@poddingue httpInactivityTimeout changed the only thing for me, I received the email half an hour later that the metadata could not be saved.

marcoi

looks like im getting the xo config backup body timeout error as well.
Xen Orchestra, commit a94eb
Master, commit 9c6d1

  "result": {
    "message": "backup task failed with undefined error",
    "name": "Error",
    "stack": "Error: backup task failed with undefined error\n    at forwardResult (file:///opt/xo/xo-builds/xen-orchestra-202608030700/packages/xo-server/src/_handleBackupLog.mjs:37:25)\n    at handleBackupLog (file:///opt/xo/xo-builds/xen-orchestra-202608030700/packages/xo-server/src/_handleBackupLog.mjs:68:12)\n    at onTaskUpdate (file:///opt/xo/xo-builds/xen-orchestra-202608030700/packages/xo-server/src/xo-mixins/metadata-backups.mjs:133:13)\n    at onTaskUpdate (file:///opt/xo/xo-builds/xen-orchestra-202608030700/@xen-orchestra/mixins/Tasks.mjs:205:23)\n    at Task.onProgress [as _onProgress] (/opt/xo/xo-builds/xen-orchestra-202608030700/@vates/task/combineEvents.js:61:5)\n    at Task.#emit (/opt/xo/xo-builds/xen-orchestra-202608030700/@vates/task/index.js:157:10)\n    at Task.#end (/opt/xo/xo-builds/xen-orchestra-202608030700/@vates/task/index.js:168:15)\n    at Task.run (/opt/xo/xo-builds/xen-orchestra-202608030700/@vates/task/index.js:190:16)\n    at Jobs.runJob (file:///opt/xo/xo-builds/xen-orchestra-202608030700/packages/xo-server/src/xo-mixins/jobs/index.mjs:297:7)\n    at Jobs.runJobSequence (file:///opt/xo/xo-builds/xen-orchestra-202608030700/packages/xo-server/src/xo-mixins/jobs/index.mjs:339:7)\n    at Task.runInside (/opt/xo/xo-builds/xen-orchestra-202608030700/@vates/task/index.js:204:22)\n    at Task.run (/opt/xo/xo-builds/xen-orchestra-202608030700/@vates/task/index.js:188:20)\n    at Api.#callApiMethod (file:///opt/xo/xo-builds/xen-orchestra-202608030700/packages/xo-server/src/xo-mixins/api.mjs:475:18)"
  }

JB

@christopher-petzel Olá Chris!
Yes, this is a local XCP-ng management network and there are no other backups simultaneous.

JB

@poddingue Olá! The failure has a fixed duration of 5 minutes.

acebmxer

Just got a failure today but with a different pool.

    "message": "backup task failed with undefined error",
    "name": "Error",
    "stack": "Error: backup task failed with undefined error\n    at forwardResult (file:///usr/local/lib/node_modules/xo-server/src/_handleBackupLog.mjs:37:25)\n    at handleBackupLog (file:///usr/local/lib/node_modules/xo-server/src/_handleBackupLog.mjs:68:12)\n    at onTaskUpdate (file:///usr/local/lib/node_modules/xo-server/src/xo-mixins/metadata-backups.mjs:117:13)\n    at onTaskUpdate (file:///usr/local/lib/node_modules/xo-server/node_modules/@xen-orchestra/mixins/Tasks.mjs:205:23)\n    at onLogFct (/usr/local/lib/node_modules/xo-server/node_modules/@vates/task/combineEvents.js:61:5)\n    at metadataBackup._executor (file:///usr/local/lib/node_modules/xo-server/src/xo-mixins/metadata-backups.mjs:122:11)\n    at Jobs.runJob (file:///usr/local/lib/node_modules/xo-server/src/xo-mixins/jobs/index.mjs:297:7)\n    at file:///usr/local/lib/node_modules/xo-server/src/api/schedule.mjs:84:9\n    at Task.runInside (/usr/local/lib/node_modules/xo-server/node_modules/@vates/task/index.js:204:22)\n    at Task.run (/usr/local/lib/node_modules/xo-server/node_modules/@vates/task/index.js:188:20)\n    at Xo.runSequence (file:///usr/local/lib/node_modules/xo-server/src/api/schedule.mjs:73:3)\n    at Task.runInside (/usr/local/lib/node_modules/xo-server/node_modules/@vates/task/index.js:204:22)\n    at Task.run (/usr/local/lib/node_modules/xo-server/node_modules/@vates/task/index.js:188:20)\n    at Api.#callApiMethod (file:///usr/local/lib/node_modules/xo-server/src/xo-mixins/api.mjs:475:18)"
  }
}

JB

Every day I update XO-CE hoping this error gets fixed, but so far, no solution!

olivierlambert

Is there a way in private message to give access to the XCP-ng host and XO VM in question OR to get all logs from 2 machines somewhere? 5min is clearly a timeout error.

acebmxer

@olivierlambert

Mine has not done it since last post but i have opened a support ticket along with tunnel being opened - Ticket#7762089

JB

@olivierlambert Yes, I can grant it.

marcoi

looks like mine also just started working.

JB

Master, commit be960

olivierlambert

@JB I'd like to test a different way of investigating the problem. So I won't do it for many people, just send me a private message with a way to SSH to your host and XOA, promise it's not a scam

JB

@marcoi Try doing it three times, and the problem comes back.

marcoi

@JB seems okay after a few back to back runs.