Overview

• When viewing Windows Server Standard requirements in Snow License Manager, the numbers reported may seem inflated.
• Snow License Manager calculates license requirement for the Host server, accounting for “License Stacking” rules across the datacenter/cluster.
• Being able to understand these numbers is key to being able to validate the data, as well as to calculate whether Windows Server Standard or Datacenter provides better value
• The objective of this article is to provide guidance and a potential example showing how this is calculated within Snow License Manager.

• For the purpose of this article we will look at Windows Server 2016 Standard (Processor Core based) application. I will specifically focus on the Host displayed below.
• As you can see, this specific host has a requirement of 288 core licenses. You should note that this is a VMware ESXI host and therefore does not have Windows server installed on the host itself.

Application Details

Clicking on the server takes you to the computers page for that machine.

Hardware Tab

• This shows processors = 2
• It also shows cores =16 per processor.
• This gives us a total of 32 cores.

Information tab

• This shows this is part of a VMware APAC Cluster 1
• It also displays that there are 32 licensable cores.

Virtual Machines tab

• Here you can see that there are 6 VMs associated to this Host.

Next, navigate to VMware APAC Cluster 1 and review the “Hosts” tab.

You can see that there is a total of 17 Virtual Machines between all 3 hosts on this Cluster.


 

Licensing

• Microsoft terms do not currently (at time of writing - please verify this is still accurate) allow you to license individual VMs, therefore, to license Windows Server VMs you must cover the host(s) accordingly.
• If you were licensing with Windows Server Datacenter, you would only need to cover the hosts for the appropriate core quantity (factoring in minimum requirements) and this would allow you unlimited VMs.
• However, as the Application we are looking at is Windows Server 2016 Standard, fully covering a host for all cores would only provide you with the rights to 2 VMs – so we would need to “stack” the Standard licenses to add the rights to more VMs. To “stack” licenses, you simply re-license the host for the correct core quantity and each time you re-license it you gain the rights to 2 additional VMs.
• Although the host only has 6 VMs the licensing rules dictate (when covering with Standard licenses) that if a cluster has high availability, all hosts must be licensed for the potential peak VM count. Therefore, if there are 17 VMs across all hosts then, one host has the potential to run 17 VMs at any one time.
• This means that we need to “stack” enough licenses to cover 17 VMs:
  • 17 / 2 = 8.5 (we round this up to 9)

The Calculation

• Each time you fully license a host with Windows Server Standard licenses, you get the right to run two VMs.
• The Physical host has a total of 32 cores.
• Therefore, each time the server is fully licensed with 32 cores you receive the rights to two VMs.
• There are 17 VMs in total. If we license the server 9 times, then 9 x 2 = 18 VMs.
• Re-license the 32 core server nine times, to unlock the VM benefit for 18 VMs. 32 x 9 = 288!