Microsoft Windows Server 2012 R2 comes with the availability of two primary editions – Standard and Datacenter. The versions are identical from a technical perspective with the only difference being virtualization rules. Both primary editions can only be licensed in the Processor Plus CAL metric . . .unlike the limited functionality editions for Windows Essentials and Window Foundation that are licensed by Server with CALs included.
So, which do you choose?
Since the functionality levels are equal, it’s something of an arithmetic issue. The licensing for Datacenter Edition is about 5½ times that of Standard Edition. Keep that in mind as we walk through the example.
Microsoft requires all physical processors on the server be licensed. Let’s assume that we have a four-processor device. Each license covers up to two processors. For this server, for either edition, two licenses are required. For Datacenter Edition, the number of virtual instances on this server would then be unlimited. It would also cost nearly $10,000 at a Select Plus Level A pricing without Software Assurance for those two licenses. It costs less than $2,000 to license it with Standard Edition, but we only get four virtual instances because with Microsoft’s Standard Edition you only get one physical instance and up to two virtual instances per license.
Now, in this example, we’re not talking about these huge servers so spinning up just four VMs might be all it can handle, but what if there was enough cycles,say, for two more? The answer is simple. From a Microsoft perspective, you just stack licenses. What Microsoft allows you to do is allocate more licenses on Windows Standard on a device than it would otherwise call for simply for the purpose of adding more virtual instances.
With this third license on that server, two more VMs can be spun up and the cost is just another $900 or so. If you still have some more room, add another for another $900. For an investment of around $3,500, a total of eight virtual instances can be deployed on that server. If that is all you could ever be on that server, you made a really good decision about going with stacking the Standard Edition licenses.