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    Can't boot a VM with 1TB memory / 128 CPUs

    Scheduled Pinned Locked Moved Compute
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    • olivierlambertO Offline
      olivierlambert Vates 🪐 Co-Founder CEO
      last edited by olivierlambert

      I remember we tested 128vCPU and it worked (Ubuntu VM, but Debian should be similar).

      htop18vcpus.png

      It was on a 2CRSi machine (1 socket however).

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

        Can you try the guest in BIOS mode in case that could change anything?

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        • F Offline
          fva-anssi @olivierlambert
          last edited by

          @olivierlambert it works in BIOS mode. The system is Dell Poweredge R7625 with AMD EPYC

          I can't go beyond 128 cores : xenopsd internal error: Xenctrl.Error("22: Invalid argument")

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

            Okay so there's 2 things:

            1. UEFI 96 cores limitation is hard coded here: https://github.com/xcp-ng-rpms/edk2/blob/5af940036ace555e5315a78a301912d294277ec0/SPECS/edk2.spec#L138 (to be invetigated)
            2. BIOS hasn't such limitation, but then you are maxing the next barrier, 128 cores, due to something else (up to 255 vCPUs)
            3. Then the "final" boss is beyond that
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            • F Offline
              fva-anssi @olivierlambert
              last edited by

              @olivierlambert Thanks a lot, the limitations of 128 cores and BIOS are fine for my usage.

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

                Thanks, feel free to reach us if you need more details on the point 2 and our progress, we can prioritize if your org is needing it.

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                • F Offline
                  fva-anssi @olivierlambert
                  last edited by

                  @olivierlambert it's for a rare usecase and we can wait for a proper fix

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                  • D Online
                    DustinB
                    last edited by

                    I can't even imagine how long a memtest would take on a box with this much ram. Ha

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

                      We are testing some machines with 6TiB RAM 😆

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                      • D Online
                        DustinB @olivierlambert
                        last edited by

                        @olivierlambert said in Can't boot a VM with 1TB memory / 128 CPUs:

                        We are testing some machines with 6TiB RAM 😆

                        My god

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