Additional Questions and Answers Regarding the VERDE Sizing Calculator

Additional Questions and Answers Regarding the VERDE Sizing Calculator

Product Line:  VERDE

Some customers have additional question regarding the Sizing Calculator.  Following are the Questions and Answers:

1) How do you calculate the number of servers from vCPU per session  and total physical CPU cores? Is one "vCPU"equal to one "thread" of the physical CPU cores? 

     ANSWER:  Verde Sizing tool uses one of the inputs called “VDI sessions per core (core-density).  Default value:  10


     This calculation creates a Pool of vCPUs by multiplying the Server physical Core x (core-density). 

     Example:  Server with 8-Cores would create a vCPU Pool using the calculation:   8-Cores times Core-density of 10 = 80 vCPUs

     This  calculated vCPU Pool is a total for the Server, that can be allocated within the Sizing spreadsheet.

     You assign this value to each Desktop using the input value:  Virtual CPUs per session (vCPU)


If you assign 2 vCPUs to 100 concurrent Desktops, your Server would require a vCPU Pool of:  200. 

Using the Core-density of 10, that means that the Server would require physical Processors with a total of 20-Cores.


2) Regarding vCPU, in the case of Windows10, the calculator recommends 4 vCPU as follows.

      Would you let me know why Windows10 requires 4 vCPU?

      Is it allowed to select 2 vCPU for Task Workers?

ANSWER:  The number of vCPUs required per Desktop is based on the Use Case.  A light-duty Office worker may be assigned a lesser number of vCPUs than another Office worker.  It is important that adequate testing is performed in order to determine what resources need to be assigned.


     We did some testing using 1 vCPU vs. 2 vCPUs with Windows 10 and had very good performance. (see the Test Results below)


RESULTS of Testing a Windows 10 Pro VM with 1vCPU assigned in Session Settings vs 2vCPUs.


The Testing included launching the following applications in both scenarios:

1.       Windows Task Manager

2.       Microsoft PowerPoint 2016

3.       Microsoft Excel 2016

4.       Microsoft Word 2016

5.       Google Chrome at the Home page (graphically busy Website)


One document was loaded into each of the MS Office applications.

A few seconds after loading the Applications and documents, we saw the CPU Utilizations drops to a low of 17% with 1vCPU and a low of 14% with 2vCPUs.


To stress the CPU, using a split screen, we were able to type into the Word document and watch the CPU Utilization rise in the Task Manager.


In the Windows 10 Pro VM with 1vCPU, the CPU Utilization rose to a high of:  68% while typing sentences into Word 2016.

In the Windows 10 Pro VM with 2vCPUs, the CPU Utilization in Task Manager rose to a high of:  34% while typing sentences into Word 2016.


So for a light-duty Task worker running MS Office and launching a Browser, they could be provisioned with 1vCPU.

For a Use Case with more demands on the Windows  10 Pro VM, it would be advised to assign 2vCPUs and a Power-User may need 4vCPUs.


3) When we select 32 cores as the total cores of one server, the total cores are 64 on two servers. Usually 64 cores have 128 threads, but 100 users need 4x100 vCPU. 

Please let me know how 64 cores satisfy the 400 vCPU needs during normal operations?

     ANSWER:  Using your Server specs with each Server having 32 Cores would yield a vCPU Pool of:  320 vCPUs    (32 x 10)

     If you assign 2 vCPUs per Concurrent Desktop, each Server would support 160 Sessions.  Calculation:  320 vCPUs divided by 2 per User = 160 sessions.

     If you assign 4 vCPUs per Concurrent Desktop, each Server would support 80 Sessions.  Calculation:  320 vCPUs divided by 4 per User = 80 sessions.


4) I received the EXCEL-based calculator last summer.

I also tried with that. However the local storage size, external shared storage size and IOPS differ from those with a web-based calculator as shown in the above table.

Does the  web-based calculator use a different calculation?

ANSWER:   The Web-based Sizing tool was created to simplify the process for a Customer.  Some of the inputs that are available in the spreadsheet version are not available in the Web-based version and use a default value.  In some cases, this can have a small impact on the results.  The Sizing Tool spreadsheet gives you more control and visibility to values being used and calculated internally.


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