How License Pooling Works in the Real World

Posey Tips and Tricks

Organizations with servers with more than 16 cores must “stack” multiple Windows Server licenses to cover all cores to ensure licensing compliance. Here’s how.

Licensing Windows Server for use is one of those things that probably seems really intuitive until you have to do it. After all, the Windows Server installation process asks for a product key, and that product key corresponds to a server license.

The catch, however, is that the Windows Server Standard Edition license is only valid for a maximum of 16 cores. The same applies to the Windows Server Datacenter license. If your server has more than 16 cores, you will have to “stack” multiple licenses to cover all the server cores. Of course, Windows Server Setup does not give you the option to enter multiple product keys. So how do you license a server that has more than 16 cores?

The first thing you need to do is figure out how many licenses you will actually need. To do this, you need to know how many cores your server has. The easiest way to find this information is to open PowerShell and enter this command:

(Get-WmiObject -Class Win32_Processor).NumberOfCores

If you look Figure 1you can see that when I typed this command, the number 28 was displayed twice. The reason why this happened is that my server contains two physical processors, and each of them has 28 cores. So the server has a total of 56 cores.

**(Click on the image for a larger view.)** *Figure 1.* My server has 56 cores.

To figure out how many licenses I need, I would divide 56 by 16, which would give me an answer of 3.5. Since you can’t half a license, I would have to round the number up to the nearest whole number, which means this server requires four 16-core licenses.

To assign a license to the server, open a command prompt window with elevated privileges and enter the following commands:

Slmgr /ipk <product key>
Slmgr /ato

The first of these two commands is used to provide Windows Server with the necessary product key. The second command activates the product key you just entered. If you are in a situation where you need to enter multiple product keys, repeat these commands for each product key. You can see how this process looks in Figure 2 and 3.

**(Click on the image for a larger view.)** *Figure 2.* Use these commands to provide Windows Server with product keys.

**(Click on the image for a larger view.)** *Figure 3.* Here’s how to activate your product key once it’s installed.

Once you are done, you can check your server’s license by entering the following command:

Slmgr /dli

If you want to see information that is more detailed, you can use a slight variation of this command. The command to use is:

Slmgr /dlv

It’s important to note that in addition to any required Windows Server licenses, you’ll also need Client Access Licenses, or CALs as Microsoft likes to call them. CALs can be purchased on a per-user or per-device basis. For example, in my organization, I opted for a User CAL because I only have a few users. However, I have dozens of devices, so it was definitely cheaper to go with a User CAL.

It’s worth noting that if you’re using Windows Server Essentials, things work a little differently. Windows Server Essentials only supports 10 cores and one physical processor. Additionally, Windows Server Essentials doesn’t require you to use CALs, but you’re limited to 25 users and 50 devices.

If you are using Windows Server Standard Edition or Datacenter Edition, you must purchase the required number of CALs. However, you do not need to install these CALs (unless you are using RDS CALs, which are used only for Remote Desktop licensing). Microsoft only requires you to track the number of CALs you have and ensure that the number of users or devices is less than or equal to the number of CALs you have purchased.

About the author

Brien Posey is a 22-time Microsoft MVP with decades of experience in IT. As a freelance writer, Posey has written thousands of articles and contributed to dozens of books on a wide range of IT topics. Before becoming a freelance writer, Posey was the CIO of a national network of hospitals and healthcare facilities. He also served as a network administrator for some of the nation’s largest insurance companies and for the Department of Defense at Fort Knox. In addition to his ongoing work in IT, Posey has spent the last few years actively training as a commercial astronaut candidate, preparing to fly on a mission to study polar mesospheric clouds from space. You can follow his spaceflight training on his website.