Licensing of Running Instances of Virtualized Windows Server
By assigning a license to a physical server, you have the right to run as many instances on that server as the software license allows. For example, Windows Server 2008 Standard permits two running instances at a time (one instance running in a physical OSE and one instance running in a virtual OSE). Windows Server 2008 Enterprise licenses permit up to five at a time (one instance running in a physical OSE and four instances running in virtual OSEs). If you choose to run all the permitted instances at a time (two under Windows Server 2008 Standard and five under Windows Server 2008 Enterprise license), the instance of the software running in the physical OSE may only be used to run hardware virtualization software, provide hardware virtualization services, or to run software to manage and service OSEs on the licensed server. However, instances of Windows Server 2008 Datacenter that run in physical OSEs do not have this limitation.
As described earlier, you may store any number of non-running instances of server software on a server or in a library. You may run these instances only on any server that is licensed. If you need to run more instances on the server than the license permits, you may assign additional licenses to the same server. By assigning several licenses to a server, you may run as many instances of the server software simultaneously as the assigned licenses combined allow.
As an example, suppose you have five licenses for Windows Server 2008 Standard assigned to a server. You may run one instance of Windows Server 2008 Standard in the physical OSE and up to five instances of Windows Server 2008 Standard in virtual OSEs on the server at the same time. The running instances could be retrieved from storage from the same or different servers or stored media.
|Instance. You create an “instance” of software by executing the software’s setup or install procedure. You also create an instance of software by duplicating an existing instance. References to software include “instances” of the software.|
Run an Instance. You “run an instance” of software by loading it into memory and executing one or more of its instructions. Once running, an instance is considered to be running (whether or not its instructions continue to execute) until it is removed from memory.
Because a server must have assigned licenses equal to or exceeding the number of running instances, you need to consider what the peak capacity for the server will be. Even if you typically only need one running instance, you must license for the peak capacity if you occasionally need a second running instance at the same time.
Licensing for Peak Capacity
For example, if you have one Windows Server 2008 Standard license assigned to a server, you may run one instance of Windows Server 2008 Standard in the physical OSE and one instance of Windows Server 2008 Standard in a virtual OSE on the server at the same time. You may not run a second instance of the software in another virtual OSE on the server. If you need to run a second instance in a virtual OSE periodically, then you must assign a second license to the server.
The following outlines the maximum number of running instances in virtual OSEs each Windows Server 2008 edition permits:
||Maximum permitted running instances in a virtual|
|Windows Server 2008 Standard
|Windows Server 2008 Enterprise
|Windows Server 2008 Datacenter
|Windows Server 2008 for Itanium Based Systems
|Windows Web Server 2008
*Windows Web Server 2008 permits you to run an instance in either one physical OSE or one virtual OSE, but not both at the same time without additional licenses. From a licensing perspective, you need a license for each instance running at the same time whether in a physical or virtual OSE.