1 2 Previous Next 18 Replies Latest reply on Aug 26, 2019 9:46 PM by jvm2016


    jvm2016 Expert

      Hi Luc,


      i am thinking to do initial vsan cluster design calculation using powercli .can you suggest if this has already been done or if we can work on creating something like this.

        • 1. Re: vsan_calculator_powercli
          LucD Guru
          User ModeratorsCommunity WarriorsvExpert

          Not too sure what you want to calculate.

          Do you mean something like the sizing exercise like Cormac mentioned in Virtual SAN – Sizing Considerations

          • 2. Re: vsan_calculator_powercli
            jvm2016 Expert

            thnaks i am checking this .however i am going to share in the form of powercli script for your suggestions.

            • 3. Re: vsan_calculator_powercli
              jvm2016 Expert

              i thought of doing in following way though its not complete yet but if you can have a look and suggest what all needs to be added to get precise storage memory cpu requirement of esxi  .



              is to migrate vms on fc backed cluster to vsan and right now in below script we are calculating resouces so that we can size vsan cluster .




              write-host "vsan capacity Planner test" -ForegroundColor Green

              $source_fc_cluster=read-host "source cluster name"

              $type_of_destination_vsan=read-host "please provide type of vsan"

              $cl=get-cluster $source_fc_cluster



              if($type_of_vsan -eq "hybrid")




              write-host "doing calculation as per inputs"

              write-host "since vsan cluster is hybrid raid option available is mirroring"

              write-host "input can be provided through csv file also"



              $vms=get-vm -Location (Get-Cluster -name $source_fc_cluster)

              $fragments_storage_thin = @()

              $fragments_memory = @()

              $fragments_vcpus = @()

              $fragments_storage_thick = @()

              $Fragments_swap_space = @()


              #$harddisks_thick=get-vm $vms|Get-HardDisk | Where {$_.storageformat -eq "Thick"}


              foreach ($vm in $vms)






              $fragments_memory += $mem_vm

              $fragments_vcpus +=  $vcpus_count_vm

              $Fragments_swap_space += $swap_space



              $harddisks_thin=get-vm $vm|Get-HardDisk | Where {$_.storageformat -eq "Thin" }

              $harddisks_thick=get-vm $vm|Get-HardDisk | Where {$_.storageformat -eq "Thick" }



              foreach ($h in $harddisks_thin)




              $estimated_capacity=$capacity + $percent_growth




              $fragments_storage_thin += $estimated_capacity




              foreach ($h in $harddisks_thick)






              $fragments_storage_thick += $capacity









              $sum_storage_thin = $fragments_storage_thin -join '+'

              $s1=Invoke-Expression $sum_storage_thin


              $sum_storage_thick = $fragments_storage_thick -join '+'

              $s2=Invoke-Expression $sum_storage_thick


              $sum_memory = $fragments_memory -join '+'

              Invoke-Expression $sum_memory



              $sum_vcpus = $fragments_vcpus -join '+'

              Invoke-Expression $sum_vcpus




              $sum_vcpus = $fragments_vcpus -join '+'

              Invoke-Expression $sum_vcpus


              $sum_swap = $Fragments_swap_space -join '+'

              $swap=Invoke-Expression $sum_vcpus




              write-host "storage requirment considering raid 1,  till now ....in GB" -ForegroundColor Gray


              • 4. Re: vsan_calculator_powercli
                LucD Guru
                Community WarriorsUser ModeratorsvExpert

                I don't think that a sizing exercise is as straight-forward as this script seems to imply.


                There is the workload aspect of the VMs to take into consideration as well.


                For example, a VM that uses only 10% of the allocated CPU and memory resources, shouldn't be taken at its configuration values.

                So, imho, you also would need to look at the workloads (performance statistics) over a period of time.

                What is the average consumption?  But also which maxima needs the environment be able to support.


                And since you want a growth margin, you will need to add spare capacity for the near future.
                How fast, and at which rate, does the environment grow (again statistical data).


                The official VSAN Sizing calculator also looks at your workloads.


                And there are people who have created spreadsheets to help with the sizing.

                See for example the VSAN 6.0 Calculator.

                • 5. Re: vsan_calculator_powercli
                  jvm2016 Expert

                  Yes this is not complete but reasons to take configured is to accommodate peak .

                  These vms are already been configured and running in fc storage .i think if I add future growth and other overhead following the same logic it can give acceptable results .


                  However I will compare with what already existing calculator .one of the calculators I checked did not have non uniform workload and also no hybrid options .


                  Checking what yu provided....

                  • 6. Re: vsan_calculator_powercli
                    jvm2016 Expert

                    Hi Luc,

                    for some reasons i am still not able to use calculators .is it possible to build on the script  assuming only configured value not the avergae values .

                    • 7. Re: vsan_calculator_powercli
                      LucD Guru
                      User ModeratorsCommunity WarriorsvExpert

                      Yes, you can use the configured values for your VMs, but as I remarked earlier, this will not expose over- and under-committed configurations.

                      • 8. Re: vsan_calculator_powercli
                        jvm2016 Expert

                        1:right now this is what i am thinking

                        in vsan environment the default  storage for vms is thin .

                        however we can make them thick to allocate space right away .

                        i am doing callculations based on thick disk and max configured values .


                        so iam trying to put following simple maths in powercli (considering ftt=1 and fault tolerance raid1)


                        2*total provisioned space+swap+futuregrowth percentage .


                        all iam stuck how to ensure one esxi failure space .

                        somehow all these planning is very much explained in vrops but we dont have so iam using powercli .



                        2:also if you could tell me how to find what storage policy configured on vm using powercli


                        • 9. Re: vsan_calculator_powercli
                          LucD Guru
                          Community WarriorsvExpertUser Moderators
                          1. What do you mean by "esxi failure space"?  Do you have a link to the vROPS article/document of the method?
                          2. To get the current storage policy, you could do


                          Get-VM | Get-SpbmEntityConfiguration

                          • 10. Re: vsan_calculator_powercli
                            jvm2016 Expert

                            thanks .

                            lets say by some method we determined that we need 4 TB space(vsan datastore) in 4 esxi hosts .

                            how to  handle one esxi failure in a cluster of 4 so that datastore  does not run out of space .

                            • 11. Re: vsan_calculator_powercli
                              LucD Guru
                              vExpertUser ModeratorsCommunity Warriors

                              I'm not that experienced in VSAN sizing to give you a simple answer to that.
                              And I'm not sure if someone can give you a direct answer with the only input being a capacity of 4TB and support for 1 node failure.

                              It all depends on many factors: the characteristics of your intended load, and the HW you will go for, the intended growth, all-flash or hybrid...

                              In short, there are no simple rules of thumb afaik.


                              Why don't you have a go with the vSAN ReadyNode Sizer?

                              It's for a specific HW type, but at least it might give you some indications of what you should be looking at.

                              • 12. Re: vsan_calculator_powercli
                                jvm2016 Expert

                                it does not have option to go beyond25 vms.

                                • 13. Re: vsan_calculator_powercli
                                  LucD Guru
                                  User ModeratorsvExpertCommunity Warriors

                                  Strange, seems to work for me.


                                  • 14. Re: vsan_calculator_powercli
                                    jvm2016 Expert

                                    Let me check again .hope yu are login as VMware account not as partner account.

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