Windows Server 2019 Essentials

This edition of Windows use a processor based licensing model and supports up to 2 CPU sockets in a single server with a single license. It is said to be ideal for small businesses with around 25 users and 50 devices.

Windows Server 2019 Standard and Windows Server 2019 Datacenter

These two editions of Windows use processor core based licensing model. For both editions:

• All physical cores must be licensed
• Minimum of 8 core licenses per processor
• Minimum of 16 cores per server

This means that if you are using a server with 2 processors, each with 8 cores, for a total of 16 cores, you only need a single license of Windows Server 2019 Standard or Windows Server 2019 Datacenter.

Note that the word "minimum" here refers to the licensing requirements— it does not mean, for example, that one cannot install Windows Server 2019 Standard or Windows Server 2019 Datacenter on a server with a processor that has only 4 cores. It means that— per licensing requirements— the first 8 cores per processor and at least 16 cores per server must be licensed.

Thus, if you have a server with a single processor that has fewer cores, or multiple processors that have a total core count that is less than or equal to the minimum, then the base license of Windows Server 2019 Standard or Windows Server 2019 Datacenter is sufficient.

However, if you are using a server with more than 16 cores, you will need the base Windows Server 2019 Standard or Windows Server 2019 Datacenter license to cover the first 16 cores, along with additional licenses (available in increments of 2, 4, or 16 cores) to cover the extra cores beyond the base 16.

Hyper-V Server 2019 and Windows Server 2019 Standard/Datacenter Virtual Machine Licensing

Hyper-V Server 2019 is free of charge, however, does not include any free virtual machine licenses. This means that all created virtual machines must be licensed individually.

Windows Server 2019 Standard licenses the use of 2 virtual machines (or alternatively, 2 Hyper-V containers and unlimited Windows Server containers) when all the cores in the host server are licensed. If additional Windows VM licenses are needed, additional licenses can be purchased to cover the total number of cores in the server again.

Windows Server 2019 Datacenter licenses the use of an unlimited number of virtual machines when all the cores in the host server are licensed.