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    VM Migrate problem

    Scheduled Pinned Locked Moved Solved Compute
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    • DanpD Offline
      Danp Pro Support Team
      last edited by

      From here --

      Check your dynamic memory setting, that's often the issue

      If that isn't it, then can only suggest that you provide additional details about your environment.

      M 1 Reply Last reply Reply Quote 0
      • M Offline
        mal @Danp
        last edited by mal

        @Danp - Thanks for your response
        Dynamic memory is a 1.4Gb.

        Receiving host has 14Gb free
        Sending host has 732Mb free however if I shut down/migrate other VMs, it makes no difference.

        Receiving host: v8.2.1 release/yangtze/master/58
        Sending host: v8.2.1 release/yangtze/master/58

        It doesn't happen with all VMs. Others (using more memory) are fine

        What else would you like to know?

        Thanks in advance

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

          Double check to have dynamic min = dynamic max = static max (so "static" memory in the end).

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          • M Offline
            mal @olivierlambert
            last edited by

            @olivierlambert - Thank you for your response

            That worked!! Brilliant!

            So, with the deprecation of DMC, it appears that it "broke" migration if you don't have dynamic=static

            Can I assume that "over commit" of memory will never be a "thing", unlike other hypervisors?

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

              No, it's not like that. Most of the time, it's because you set up a dynamic min that's too low.

              As soon as you migrate, Xen will "balloon out" the memory and go down to dynamic min.

              However, if your VM system is reduced to 1.5GiB (in your case) and can't handle it, it will just fail. So DMC is probably working if your dynamic min was higher.

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              • M Offline
                mal @olivierlambert
                last edited by

                @olivierlambert
                Understand and thanks for the explanation.

                Also, appreciate the brilliant effort you and the team put in.

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                • M Offline
                  mal @olivierlambert
                  last edited by

                  @olivierlambert

                  I have a similar issue with a different VM where it fails with:

                  Not enough server memory is available to perform this operation.
                  needed: 2167406592
                  available: 1543491584
                  

                  however the host has 9.5Gb free (according to XO). VM has static=dynamic=2Gb

                  Sorry, but what am I missing this time?

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                  • M Offline
                    mal @mal
                    last edited by

                    @mal

                    Restarting the toolstack allowed me to move the VM. More work-around than fix, I feel!

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

                      This means your host had not enough memory (only 1.4GiB free when computing all the dynamic max range combined on all your VMs). That's the catch with dynamic memory, it's quickly messy.

                      Can you confirm that you have other VMs with higher dynamic max on this host?

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                      • M Offline
                        mal @olivierlambert
                        last edited by mal

                        @olivierlambert

                        Unfortunately I've moved VMs around (this is all testing at the moment) however there were other VMs with static=dynamic=2Gb which I could move.

                        Could you please either explain or point me to the documentation where I can understand how your comment works, please?

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