Many customers are looking at consolidating the datacenter with Virtualization technology. This article is to provide a quick run down of the approach to Windows Server Virtualization using VMware Technology.
One common scenario that IT Pros look at is VMware server running a virtual guest, Windows Server 2008.
The approach Microsoft takes is to look at the licensing of Windows Server independent of VMware. Windows Server licensing does incorporate Virtualization by providing a number of virtual guests based on licensing the physical server. For example;
Physical Operating System (POSE) + Virtual Operating Systems (VOSE)
Windows Server 2008 Standard 1* + 1
Windows Server 2008 Enterprise 1* + 4
Windows Server 2008 Datacenter 1* + Unlimited
*If running the maximum allowed instances, the instance in the physical operating system environment may only be used to run hardware virtualization software (for instance VMware or Hyper-V), provide hardware virtualization services, or run software to manage and service operating system environments on the licensed server.
So based on a VMware host, a customer would license all the physical processors on their server for the base Windows Server license, and then they would be entitled to run up to the number of virtual guests allowed by the base OS license.
An IT Pro acquires a IBM server with VMware and wants to have 16 windows virtual machines on that server:
If he or she needs to run 16 instances on one single box with VMware, they can either purchase 1u Windows Server Datacenter, 4u Windows Server Enterprise or 16u Windows Server Standard.
A Windows Server® Standard licence allows the use of one physical plus one virtual OSE (Operating System Environment) providing the physical OSE is only managing the virtual OSE. Please be advised that additional OSEs will require an additional license. This is often referred to in shorthand as 1+1.
One Windows Server® Enterprise edition licence allows one physical plus four virtual OSEs. If the physical OSE was also running applications, then only three virtual OSEs would be permitted. Each software license allows you to run, at any one time, four instances of the server software in four OSEs on one server. If all four instances you run are in virtual OSEs, you may also run an instance in the physical OSE solely to run hardware virtualization software, provide hardware virtualization services, or run software to manage and service OSEs on the licensed server. This is often referred to in shorthand as 1+4.
Windows Server® Datacenter edition allows one physical and unlimited virtual OSEs. After the number of licenses equal to the number of physical processors on a server are acquired and assigned, you may run on that particular server: One instance of the server software in the physical OSE, and any number of instances of the server software in virtual OSEs.
Hint – What does assigning a license mean?
To assign a license simply means that you designate that license for one device or user. This designation avoids sharing a license across more than one device or user at the same time. For example, after you have assigned a software license to a server, you are permitted to run the software on that server. You may use whatever manual or technical method that works for you to ensure that you have the correct number of licenses to cover your software use. [Ref: Licensing Microsoft Server Products in Virtual Environments]