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    VM failed and won't start. Displaying "An emulator required to run this VM failed to start"

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    • R Offline
      rustylh
      last edited by

      Additional finding. The two switches (LAG) are Cisco with STP enabled.

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      • R Offline
        rustylh
        last edited by

        I am still getting " sd 7:0:0:1: rejecting I/O to offline device" taking all VMs on host down. I then shutdown the VM and power them on, on another Host. I have 4 host in a pool connected iSCSI to a Synology LUN. What is the best way to troubleshoot network issues on xcp-ng.
        Thank you

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        • R Offline
          rustylh
          last edited by

          Just adding another note. When I reboot the host everything is fine then the issues pops back up. There doesn't seem to be any consistency as far as timeframe in between. It just happens randomly

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          • R Offline
            rustylh
            last edited by

            Any help is greatly appreciated.

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            • olivierlambertO Offline
              olivierlambert Vates 🪐 Co-Founder CEO
              last edited by

              That's not a trivial problem that you have, it seems to be intermittent and could be anything between host and the storage. I assume you can see the issue as soon you have the rejecting I/O to offline device right?

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              • R Offline
                rustylh
                last edited by

                Yes

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                • olivierlambertO Offline
                  olivierlambert Vates 🪐 Co-Founder CEO
                  last edited by

                  At least we know there's a root cause: the device becomes offline. Could it be a power setting or something on the device itself?

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                  • R Offline
                    rustylh
                    last edited by

                    Well, it doesn't happen to every host at the same time, it's just random.

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                    • R Offline
                      rustylh
                      last edited by

                      What log is best to look at for network disconnects?

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                      • olivierlambertO Offline
                        olivierlambert Vates 🪐 Co-Founder CEO
                        last edited by

                        Well dmesg is fine, I would also check the switch logs if you have anything happening on the ports where you host are connected. Since you can find when it's happening with dmesg, I would use that to correlate with anything else happening few minutes before.

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                        • R Offline
                          rustylh
                          last edited by

                          dmesg -T is only showing these from 00:37 on.

                          [Mon Jun 30 05:55:10 2025] print_req_error: I/O error, dev sdb, sector 0
                          [Mon Jun 30 05:55:10 2025] sd 7:0:0:1: rejecting I/O to offline device

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                          • olivierlambertO Offline
                            olivierlambert Vates 🪐 Co-Founder CEO
                            last edited by

                            Then try to find anything happening around that time on other hosts, equipment, storage and so on.

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