How to buy Windows Server 2012
What are my options?
There are four ways to run multiple WS2012 servers, which means four ways to license it:
1.Natively on physical hardware
Yesteryear's approach, I know, but there is still the option of running WS2012 on a physical server. I'm not expecting to see many Foundation Edition installations, but small business may well adopt the Essentials Edition. Larger companies will need Standard Edition simply for its support of more than 25 users. The rule is simple: with Standard or Datacenter you'll need a licence for every two processors in your server, remembering that if you have single-processor servers you can't split a licence between two servers.
2. Virtually using WS2012 virtualisation
This is an interesting one, because now the concept of an Enterprise Edition has been retired, only the Datacenter Edition supports more than one virtual instance. So businesses that want to virtualise with Hyper-V will find themselves signing up to Datacenter instead. If you want a handful of virtual machines (fewer than 10 or so), buy multiple standard licences to cover them; and if you want to go massively virtual buy Datacenter. Remember though, if you're using Standard you will need to license the workloads independently, as you will always need to license for the maximum number of machines that may run on host.
3. Virtually using other virtualisation platforms
With the introduction of WS2012 this is probably the hardest option to justify, particularly if you don't already have a significant virtual server estate. If you're an ESX house then of course you'll think long and hard before deciding to change horses and adopt Hyper-V instead. As we've seen, though, Microsoft has clearly caught up a great deal of ground on its competitors with the major effort it's made to bring the features of Hyper-V up to date. Don’t take our word for it, why not do a cost comparison for yourself, http://cloudeconomics.cloudapp.net
Frankly, then, if you're about to embark on a new virtualised server estate it'll be hard to justify adopting two technologies (Windows plus a third-party virtualisation platform) instead of just one (Windows with Hyper-V).
It's perfectly feasible, of course, to decide to stick with an existing non-Microsoft virtualisation platform – VMware ESX being the obvious one. We'll come back to that shortly as it's a special case.
4. In the cloud
If you prefer the zero-installation option, the obvious way to go is to let a cloud provider install and manage it for you. It's no surprise that Windows Azure already has WS2012 available as a target operating system, and by the time you've waited the customary few weeks to let others find the big, scary bugs the other big providers will have jumped on the bandwagon. In the Cloud you don't care (at least as far as virtualisation is concerned) how many processors you have, or how many VMs you're running; instead you simply pay for the power you need and the Cloud provider deals with the licensing so you don't have to.
Although we've said that it's hard to justify something other than Hyper-V for a new installation, there are tens of thousands of organisations out there who have the likes of VMware and have no desire to replace it overnight just for the sake of adopting WS2012.
Microsoft has had a habit of using a couple of dozen words where ten will do in its licensing documentation but this time, however, it is really pretty simple once you've found the pertinent bit: "All physical processors need to be licensed. Each license covers up to two physical processors."
In short: forget you've got the underlying virtualisation layer and just license it as if you were using Hyper-V. So all the physical processors in a physical server need to be licensed (so that's one licence for each pair of processors or part thereof), and if you're running Standard Edition you can run two VMs per licence. So eight VMs on a twin-CPU server needs a single Datacenter licence or four Standard licences, and for 60 VMs on a four-CPU server you'd buy two Datacenter licences as it'll be cheaper than a boatload of Standard ones.