Untangling Windows' DaaS licensing knots
Depending on how you do it, desktop as a service (DaaS) has the advantage of fairly low and predictable costs. Still, some deployment models can up the price tag considerably when shops are forced to factor in Windows licensing costs. If you want to host Windows client OSes, such as Windows 7 or 8, you have to bring your own Software Assurance (SA) or Virtual Desktop Access (VDA) licenses; there isn’t a Service Provider Licensing Agreement (SPLA) for VDA, which shops need to run Windows client OSes. That makes hosting Windows 7 desktops about as expensive as doing VDI in-house. There is an SPLA for Windows Server operating systems, however. Using that model is how companies can keep DaaS costs low and predicable, but they do so at the risk of application compatibility issues that come with using server-based OSes. What's more, it doesn't benefit Microsoft to set up SPLA for VDA, so there might not be a fix in the near future, even despite changes to SA licensing rules.