Introduction to Microsoft Core licensing models

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If you’re new to Microsoft licensing one of the most basic concepts you need to learn about is understanding the Core licensing model. It’s Microsoft preferred metric for measuring computing power and keeping things consistent across different environments. Like, whether you’re using physical servers, virtual machines, or the cloud, core-based licensing has got you covered. Plus, it makes it super easy to move between different environments, which is a total game-changer compared to the older licensing models.

There are three main licensing models that use different flavors of Per Core licensing:

1. SQL Server and BizTalk Server use the Per Core licensing model.
2. Windows Server (Standard and Datacenter) uses the Per Core/CAL licensing model.
3. And System Center (Standard and Datacenter edition) uses the Management Servers (core-based) licensing model.

So, whether you’re running SQL Server, BizTalk Server, Windows Server, or System Center, you can trust that Core-based licensing has got your back

Per Core model

There are two ways to go about it: licensing based on Physical Cores on a Server or licensing by Individual Virtual Machine.

So if you’re running the software on a physical server, you need to license all the physical cores on that server. No shortcuts or workarounds. And you need a minimum of four core licenses for each physical processor on the server.

But here’s the good news: with the Per Core model, you don’t need to buy any extra client access licenses (CALs) for all the users or devices that want to connect to the server.

Now if you’re running the software in virtual machines, it’s a little different. You need to license all the virtual cores (or v-cores) supporting the virtual machines running the software. And you need a minimum of four core licenses per virtual machine.

And for Enterprise editions, for each server you’ve licensed, you can run as many instances of the server software in physical OSEs and/or virtual machines as you have licenses for. And for each additional license, you can run another instance of the software in another OSE. But for Standard and other editions, you can only run instances of the software in the physical OSE.

Per Core + CAL model

Since October 2022, there are two ways to license the Per Core/CAL model. (1) You can either license based on the physical cores on the server, or (2) by virtual machine. But, here’s the catch: you can only license by virtual machine if you’ve got a subscription license or one with active Software Assurance.

When you’re licensing based on physical cores, you need to license all the physical cores on the server you’re running the software on. The server has to be assigned a minimum of 16 core licenses, with a minimum of 8 core licenses per physical processor. Whichever of those two requirements is greater, that’s the minimum number of licenses any server running the software needs to have.

The Datacenter edition allows you to run the software in the physical OSE and any number of virtual machines on the licensed server. The Standard edition, on the other hand, lets you run the software in up to two OSEs (physical or virtual) on the licensed server. If you’re running the software in two virtual machines, you can also run the software in the physical OSE if it’s being used solely to host and manage the virtual machines.

If you like containers, you can use Windows Server Containers with either edition. With the Datacenter terms, you can use any number of Windows Server Containers with or without Hyper-V isolation on servers licensed based on physical cores. With the Standard terms, you can use two Windows Server containers with Hyper-V isolation and unlimited Windows Server containers without Hyper-V isolation on servers licensed based on physical cores.

If you’re using the Standard edition and want to use more virtual machines or Windows Server Containers with Hyper-V isolation, you can either fully relicense the server based on physical cores, or if you’ve got active Software Assurance on your Standard licenses.

Management Servers model

Since the changes in October 2022, there are two ways to license the Management Servers: by physical cores on a server or by virtual machine. But, you can only license by virtual machine if you have a subscription license or Software Assurance.

If you’re licensing by physical cores, you gotta license all the physical cores on the server you’re managing OSEs on. You need at least 16 core licenses, with a minimum of 8 core licenses per physical processor.

If you’re using the Datacenter edition, you can manage any number of virtual machines on the licensed server. But with the Standard edition, you can only manage up to two OSEs (physical or virtual) on the licensed server.

If you need to manage more than two OSEs on a server licensed for Standard, you can “stack” more licenses or purchase Step Up licenses to the Datacenter edition. If you’re licensing by virtual machine, you need to license all the virtual cores in the virtual machine you’re managing. And, you need at least 8 core licenses per virtual machine, and a minimum of 16 core licenses per customer. Just keep in mind, licensing for managing client OSEs is subject to different terms – check out the Microsoft Product Terms for that info.

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