Upgrading and migrating servers and workloads

In most cases, Windows Server 2016 will be deployed in environments that are already in production, meaning existing Windows Server editions prior to Windows Server 2016 will most likely already be on the hardware. Obviously, you will eventually need to perform a bare metal installation of Windows Server 2016 on some computers. It is also possible that you will need to change to a different Windows Server 2016 edition on an existing Windows Server 2016 installation, too. The two main approaches to install Windows Server 2016 are as follows:

• Migration: Migration is the preferred method for installing Windows Server 2016 and involves two computers. The first computer already runs a version of Windows Server, from which roles are moved. The second computer has a freshly installed Windows Server version, to which roles are moved.

The term migration is not specific just to Windows Server 2016, but to any operating system version and it always involves two computers. Therefore, migration can be defined as moving one or more roles or features and their data from one computer to another computer, not upgrading that role or feature on a same computer. In this way, newly installed computer does not inherit bad configuration data, or old and unnecessary files from the old computers. This is the way that Microsoft recommends that you move existing workloads to a computer running the most recent Windows Server 2016 version.

• Upgrade: While migration involves two computers, upgrading only involves one computer. If you have a Windows Server machine configured and running but you want to keep the existing hardware, configuration, and installed applications, you should choose to do an upgrade instead of a migration. This process involves copying newer installation files to an existing, usually older, Windows Server installation version. This limits available upgrade options. Not every combination of older and newer Windows Server versions is supported, so you have to take supported upgrade paths into consideration.

The following table lists supported upgrade paths from older Windows Server versions to Windows Server 2016 version:

Upgrade from version	Upgrade to version
Windows Server 2012 Standard	Windows Server 2016 Standard or Datacenter
Windows Server 2012 Datacenter	Windows Server 2016 Datacenter
Windows Server 2012 R2 Standard	Windows Server 2016 Standard or Datacenter
Windows Server 2012 R2 Datacenter	Windows Server 2016 Datacenter
Hyper-V Server 2012 R2	Hyper-V Server 2016 (using the Cluster OS Rolling Upgrade feature)
Windows Server 2012 R2 Essentials	Windows Server 2016 Essentials
Windows Storage Server 2012 Standard	Windows Storage Server 2016 Standard
Windows Storage Server 2012 Workgroup	Windows Storage Server 2016 Workgroup
Windows Storage Server 2012 R2 Standard	Windows Storage Server 2016 Standard
Windows Storage Server 2012 R2 Workgroup	Windows Storage Server 2016 Workgroup

Transitioning to a newer Windows Server 2016 operating system is also not possible the following circumstances:

• Upgrading from Windows Server with a GUI to Windows Server Core edition. However, in prior versions, transitioning from Windows Server 2012 (or R2) Core edition to Windows Server 2012 (or R2) with a GUI is possible. After transitioning, you can proceed to upgrade.
• Upgrading from Windows Server Core edition to Windows Server with a GUI. Like in the previous scenario, prior to upgrading, transitioning from Windows Server 2012 (or R2) with a GUI to Windows Server 2012 (or R2) Core edition is possible, following which, upgrading is possible.
• Upgrading from one language to another, for example from an Italian edition of Windows Server 2012 to a Swedish version of Windows Server 2016.
• Upgrading from a licensed version of Windows Server to an evaluation version of an operating system.
• Upgrading from a 32-bit to a 64-bit architecture.

Converting from an evaluation version of a Windows Server operating system to a licensed Windows Server 2016 version is possible. To check whether the operating system is an evaluation version, open System and Security and then click on System in the Control Panel. View Details will show you the license information. Alternatively, from an Command Prompt, type slmgr.vbs /dlv or DISM /online /Get-CurrentEdition to check the edition information. After that, type DISM /online /Set-Edition:<edition ID> /ProductKey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX /AcceptEula to convert an evaluation version of an operating system to a retail version.

License conversion

Converting a release of an operating system to a different release of the same version is called a license conversion.

The following table shows license conversion paths:

Convert from	Convert to
Windows Server 2016 Standard	Windows Server 2016 Datacenter
Windows Server 2016 Essentials	Windows Server 2016 Standard
Windows Server 2016 Standard (evaluation)	Windows Server 2016 Standard (retail)Windows Server 2016 Datacenter (retail)

Automatic Virtual Machine Activation (AVMA)

AVMA has existed since Windows Server 2012. It is a feature that automatically activates virtual machines on Windows Server 2016 Hyper-V hosts if the host operating system is activated. The activation works even in disconnected systems. During activation, special AVMA activation keys must be used to activate virtual machines.

The following AVMA keys can be used for Windows Server 2016:

Edition	AVMA key
Datacenter	TMJ3Y-NTRTM-FJYXT-T22BY-CWG3J
Standard	C3RCX-M6NRP-6CXC9-TW2F2-4RHYD
Essentials	B4YNW-62DX9-W8V6M-82649-MHBKQ

Key Management Services (KMS) activation

KMS activation uses a client-server model for client or server operating system activation. The KMS service can reside on a client or operating system; it does not have to be a dedicated server. The KMS service can coexist with other services without operational issues.

A computer that has the KMS service installed is called the KMS server or the KMS host, while computers that connect to a KMS host to perform an activation are called KMS clients. Only KMS clients that reside on the same network as the KMS host can connect to that KMS host and perform an activation.

You can install the KMS host on a virtual or physical computer running any of the following operating systems: Windows 10, Windows Server 2016, Windows Server 2012 R2, Windows 8.1, or Windows Server 2012. If the KMS service is installed on a client operating system, only client operating systems can be activated, so a KMS host installed on Windows 10 or Windows 8.1 cannot activate Windows Server editions. A single KMS host can support an unlimited number of KMS clients and it is recommended that you have at least two KMS hosts in a larger environment in case one activation server becomes unavailable.

A KMS host activates KMS clients based on a minimum number of activation requests, or the threshold level. The KMS clients are activated in bulk. The threshold level for server operating systems and Microsoft Office volume editions is five, while the threshold level for client operating systems is 25. The threshold levels also apply to the period in which clients submit requests for activation. This period is 30 days and is applicable to the 50 most recent contacts.