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    Memory in vm half as fast after migration of vm.

    Scheduled Pinned Locked Moved Compute
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    • A Offline
      Andreas @olivierlambert
      last edited by

      @olivierlambert Okay I'll try it but where do I see if it has dynamic memory
      i xen Orchestra?
      I have previously used xcp-ng center.

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

        Advanced view of the VM, check if static max = dynamic min = dynamic max.

        A 2 Replies Last reply Reply Quote 0
        • A Offline
          Andreas @olivierlambert
          last edited by olivierlambert

          @olivierlambert no it says

          Static: 512 MiB / 32 GiB
          Dynamic: 1 GiB / 32 GiB
          

          should I change to this to make it static

          Static: 32 GIB / 32 GiB
          Dynamic: 32 GiB / 32 GiB
          

          because I do not see where I can delete Dynamic

          olivierlambertO 1 Reply Last reply Reply Quote 0
          • A Offline
            Andreas @olivierlambert
            last edited by olivierlambert

            @olivierlambert
            I have set it to this

            Static: 512 MiB/32 GiB
            Dynamic: 32 GiB/32 GiB
            

            could not change static value

            okay did a migration again
            but unfortunately the same result

            Before migration

            #redis-benchmark -r 1000000 -n 2000000 -t get,set,lpush,lpop -P 16 -q
            SET: 223363.84 requests per second
            GET: 235793.44 requests per second
            LPUSH: 247954.38 requests per second
            LPOP: 251572.33 requests per second
            

            After migration

            #redis-benchmark -r 1000000 -n 2000000 -t get,set,lpush,lpop -P 16 -q
            SET: 111844.31 requests per second
            GET: 118119.54 requests per second
            LPUSH: 116083.34 requests per second
            LPOP: 116795.14 requests per second
            

            After reboot off VM on the second server

            #redis-benchmark -r 1000000 -n 2000000 -t get,set,lpush,lpop -P 16 -q
            SET: 244468.91 requests per second
            GET: 254647.31 requests per second
            LPUSH: 261848.66 requests per second
            LPOP: 261574.69 requests per second
            
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            • olivierlambertO Online
              olivierlambert Vates 🪐 Co-Founder CEO @Andreas
              last edited by

              @andreas That's the correct way to do it, indeed.

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              • A Offline
                Andreas @olivierlambert
                last edited by

                @olivierlambert Yes, but the problem remains
                how can you troubleshoot this or is it in xcp-ng?

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

                  You should probably start to compare XAPI record for the VM, before and after the migration, in case anything changed.

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                  • A Offline
                    Andreas @olivierlambert
                    last edited by

                    @olivierlambert XAPI records this is a bit beyond my knowledge.
                    I tried to make a brand new VM Ubuntu 20.04 server
                    just to see so it was not the virtual machine it was wrong in but
                    unfortunately the same result again.

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

                      xe vm-param-list uuid=<VM UUID>. Compare the output before and after migration.

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                      • A Offline
                        Andreas @olivierlambert
                        last edited by

                        @olivierlambert
                        Okay find a value that is different
                        the test is done on the new VM which has 6 GIB in Ram
                        This is the value before migration
                        memory-target ( RO): 0
                        after migration
                        memory-target ( RO): 6442450944
                        and after reboot of VM
                        memory-target ( RO): 0

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

                          That's weird, despite the fact your VM is set to static, right? (same dynamic min, max and static max?)

                          edit: is it the only diff?

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                          • A Offline
                            Andreas @olivierlambert
                            last edited by Andreas

                            @olivierlambert
                            no this change from this
                            memory-actual ( RO): 6442455040
                            to this
                            memory-actual ( RO): 6442450944

                            and its below but they probably have no significance
                            start-time
                            console-uuids
                            dom-id
                            VCPUs-utilisation
                            guest-metrics-last-updated
                            b2471d1e-2d28-44c6-af0e-c555e9ecf100-image.png

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

                              That's weird. We'll see if we can reproduce this. @Darkbeldin will try when he can (probably in January)

                              A 1 Reply Last reply Reply Quote 0
                              • A Offline
                                Andreas @olivierlambert
                                last edited by

                                @olivierlambert
                                Okay thanks
                                and happy New Year 🙂

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

                                  You too!

                                  A 1 Reply Last reply Reply Quote 0
                                  • A Offline
                                    Andreas @olivierlambert
                                    last edited by

                                    @olivierlambert
                                    Sorry to disturb you.
                                    Okay just to verify that there was nothing wrong with the physical servers.
                                    So I took 2 identical PCs and installed clean new xcp-ng 8.2
                                    then install a virtual machine with static 4GB of memory and with guest tools.
                                    Install redis and ran the test
                                    then migrated VM to other pc and ran the test and the speed was half.
                                    Took out the result before and after attached the files.

                                    1.Before migration.txt
                                    2.After migration.txt

                                    DarkbeldinD 1 Reply Last reply Reply Quote 0
                                    • DarkbeldinD Offline
                                      Darkbeldin Vates 🪐 Pro Support Team @Andreas
                                      last edited by

                                      @andreas Hi Andreas,

                                      After testing it on my side i can confirm i reproduce the issue.
                                      I will discuss it at dev level and get back to you.

                                      A ForzaF 2 Replies Last reply Reply Quote 2
                                      • A Offline
                                        Andreas @Darkbeldin
                                        last edited by

                                        @darkbeldin
                                        Okay Thanks

                                        DarkbeldinD 1 Reply Last reply Reply Quote 0
                                        • ForzaF Offline
                                          Forza @Darkbeldin
                                          last edited by

                                          @darkbeldin said in Memory in vm half as fast after migration of vm.:

                                          @andreas Hi Andreas,

                                          After testing it on my side i can confirm i reproduce the issue.
                                          I will discuss it at dev level and get back to you.

                                          This seems quite an important find. Please let is know how this goes.

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                                          • DarkbeldinD Offline
                                            Darkbeldin Vates 🪐 Pro Support Team @Andreas
                                            last edited by Darkbeldin

                                            @andreas

                                            So I was doing some testing before reporting to dev team and I have a behavior I will like you to check if you reproduce:
                                            my clean VM report like this

                                            yachy@ubuntuyachy:~$ redis-benchmark -r 1000000 -n 2000000 -t get,set,lpush,lpop -P 16 -q
                                            SET: 156152.41 requests per second
                                            GET: 168180.28 requests per second
                                            LPUSH: 156421.08 requests per second
                                            LPOP: 159757.17 requests per second
                                            

                                            That's my reference, when I migrate to another host it report like this:

                                            yachy@ubuntuyachy:~$ redis-benchmark -r 1000000 -n 2000000 -t get,set,lpush,lpop -P 16 -q
                                            SET: 55718.07 requests per second
                                            GET: 58683.72 requests per second
                                            LPUSH: 55742.91 requests per second
                                            LPOP: 54775.01 requests per second
                                            

                                            If I reboot it goes back to original reporting but if I migrate back to the original host without rebooting it report like that.

                                            redis-benchmark -r 1000000 -n 2000000 -t get,set,lpush,lpop -P 16 -q
                                            SET: 138092.94 requests per second
                                            GET: 153151.08 requests per second
                                            LPUSH: 147004.78 requests per second
                                            LPOP: 148115.23 requests per second
                                            

                                            So not perfect as reference but way better than after migration.
                                            As I want to be thorough before reporting could you check if you reproduce that?
                                            So:

                                            • migrate to another host
                                            • make the test
                                            • migrate back to the original host
                                            • make the test

                                            Thanks for your help.

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