What licenses do I need to get a virtual desktop environment up and running?

Question

I’m trying to figure out what licenses I need to get a full Windows Virtual Desktop Infrastructure (VDI) up and running with the Remote Desktop Service (RDS) roles.
I have Win.Server 2012 running Hyper-V, which has about 10 different virtual machines (VM) with either Win.7 or Win.8 installed on it. These VMs will act as virtual desktops (VD) for about 200 people to remotely access and use.
My question is, what licenses do I need to support this scenario?
So far, I’m planning to purchase a few Windows Server 2012 Standard Edition with 10 Client Access Licenses ( $1414.19 each). I’m assuming that’s 1 license for the server and 10 Client Access Licenses (CAL) for users who will access the VDs. I’m also planning
to buy about 200 RDS CALs ($149 each) for the rest of the users to access the VDs. Do I need to buy additional licenses for each VM image I create (the 10 images I mentioned earlier)? These VMs are in a pooled virtual desktop collection, so they reset themselves
when users disconnect from them. If I have personal desktop collections which give unique desktops to each user and saves their settings, will my license have to change if I have that too?
At first I thought just buying the RDS CALs will allow me to install windows where ever I want, how many times I want and all I have to worry about is paying for the client access, but do I need to pay for the OS as well? So essentially I’m doubling the
license?
A side question not really related is, if I have Windows Thin PC, (which was said to come free if I have SA with another product)  and bought the Windows Server license, does that come with SA and I can install Windows Thin PC as many times as I want
on which ever desktop I have that will connect to this VDI system?

Answer 1

The 10 server licenses are fine, but they don't help you with VDI or remote desktops. I you want to install the Remote Desktop Session Host (formerly known as Terminal Server) role on all your servers und provide remote desktops for your 200 users, 200 RDS
CALs are the right choice (per user or per device).
But if your 200 users have access to virtual desktops, you need 200 VDI licenses. It doesn't matter if you only have 10 virtual desktops if potentially all your 200 users have access to them. VDI licensing is not based on a concurrent model, so every client
that can connect to a VM needs its own license. If Windows 8 Enterprise with SA is on all your client devices, you're set because SA gives users access rights to up to 4 Win8 or Win7 VMs concurrently (local or remote). In addition
it gives them a so-called companion subscription license for personally owned, non-primary devices.
For those primary corporate devices that are without SA, you'll need to purchase a single VDA license for each device that connects to any number of your Win7 or Win8 VMs. The same applies to personally owned devices of users who don't have a primary
corporate device with SA. In other words, BYOD is supported if your primary device is under SA.
For neither VDI/SA nor VDA it does matter if users are connecting to different VM images or only one. Typically, they cannot connect to more than 4 VMs at the same time in order to stay within the licensing limits.
Benny