Microsoft VDI Licensing

Q: (from Kellie)

If an end user is hosting virtual desktops on a server, is there a limit to the number of virtual desktop instances they may run? If so, is the limit different for Standard and Datacenter?

I know VDA is required to license the devices accessing a Virtual Desktop and VDA is available with SA or as a standalone license in OV for devices that don’t qualify for SA. In reading through various documents, it does not appear that VDI suite is required, but includes additional features that are optional. It becomes confusing to know when the VDI suite is needed or when RDS CALs are needed. Is there a brief explanation that you can provide that would help us understand exactly that is needed in setting up a Virtual Desktop scenario where desktops are virtualized on a server? Any assistance would be greatly appreciated. Thank You!



Windows Server nor the Hyper-V limits the number of virtual sessions hosted under Hyper-V; regardless of the virtual sessions being VDI, Windows Servers, or some other virtual machine. Performance would be limited by the physical resources (memory, disk space, processor, etc.). Windows Server Standard, however, only provides 2 virtual SERVER licenses, but you can host more servers if you have licensed them some other way.

VDI is handled the same basic way: as long as your hardware is capable, you can host as many VDI sessions under Hyper-V as you want, as long as the VDI sessions are properly licensed (as you confirmed in your question above)

Regarding how to license VDI / VDA / RDS, here is the most recent FAQ I could find. It looks reasonably current aside from the reference to Windows 7 instead of Windows 8.

To answer your VDA & RDS vs. VDA & VDI Suite question:

  • As you stated, you have to have either Windows with SA or a VDA license per device accessing the virtual desktop
  • You also need an RDS license per accessing device. This can either be an RDS CAL or the RDS included in the VDI Suite. The difference is that the RDS included in the VDI Suite can’t be used to access “Session Based” RDS (aka. traditional Terminal Services) only the parts of RDS that are needed to support VDI (the connection broker and gateway)
  • We also recommend a management tool, but that is not required. The VDI Suite includes the System Center RDS Client Management License.

My brain hurts – but this is the first time that I’ve found enough information to make the VDI / VDA / RDS licensing make sense to me, I hope it helps you.


SDeming Face  Steve

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