6 Replies Latest reply on Mar 26, 2020 8:55 AM by a.p.

    Not enough CPU capacity

    SirHaschke Enthusiast

      Hi,
      we have a VM with 12 CPUs and a reservation 21800 MHZ.

      If i try to set it to 16 CPUs with reservation 35000 MHZ i get this error:

      Unbenannt.JPG

      We use 2 Servers in the cluster with this HW:

      Unbenannt1.JPG

       

      Why can't i set a reservation with 35000 Mhz?

       

      Regards

      Dennis

        • 1. Re: Not enough CPU capacity
          bewe Hot Shot

          because 2.1 * 16 = 33600 MHz - try that number

          • 2. Re: Not enough CPU capacity
            scott28tt Champion
            Community WarriorsVMware EmployeesUser Moderators

            What is the VM doing to warrant 16 CPUs with a full reservation?

            • 3. Re: Not enough CPU capacity
              a.p. Guru
              vExpertUser ModeratorsCommunity Warriors

              How many VMs are running on that cluster, and how is HA (Admission Control) configured?

              You may see whether the VM starts with HA being disabled, to find out if it's a configuration issue?

               

              André

              • 4. Re: Not enough CPU capacity
                SirHaschke Enthusiast

                bewe

                Ah, ok. And if i take 18 Proc. then i can set an reservation from 37800 MHz.....

                 

                scott28tt

                This is a conferencing system from our telephone system.
                The manufacturing company has this as System requirements.

                 

                a.p.

                ca. 40 VMs on 2 physikal ESXi servers.
                HA is Active, but only Active for one VM because the other VMs are created redundantly.
                The phone manufactor have an own HA.

                • 5. Re: Not enough CPU capacity
                  scott28tt Champion
                  Community WarriorsVMware EmployeesUser Moderators

                  Those "requirements" may be intended more for physical than virtual environments - you may find that performance is acceptable with fewer CPUs for the VM, in fact it may even be better given how easier it makes things for the ESXi CPU scheduler.

                   

                  I would definitely recommend testing the app to see what CPU resources are REALLY needed.

                  • 6. Re: Not enough CPU capacity
                    a.p. Guru
                    vExpertUser ModeratorsCommunity Warriors

                    Interesting that some of the phone/conferencing system providers still seem to have no clue about how virtualization works.

                    Anyway, with the defaul HA settings, vSphere calculates minimum slot sizes based on the highest reservation on any of the VMs. These minimum slot sizes are then assumed for each powered on VM, that's why HA refuses to power on the VM.

                     

                    Options are:

                    • if the vendor insists on VM reservations, then either reconfigure Admission Control from the default settings, to percentage settings, or set fixed slot sizes (CPU, and RAM) with smaller values, e.g. 256MHz, and 256MB.
                    • other than this, creating a Resource Pool for this one VM, and configure the reservations on the pool, rather than on the VM itself should work too.

                    André

                    1 person found this helpful