So here as I sit typing Brian Madden is in front of me, filming one of my other colleagues, Eric Schroeder talk about installing the Microsoft VDI solution as part of the Brian Madden VDI shootout. We have been here all day, talking about the architecture and getting the servers up and running. A second ago I was up with Brian whiteboarding out the architecture. It should be pretty cool to see!
Its important to note that the Microsoft VDI solution is based on two core platforms: Windows Server 2008 R2 and Windows 7. Remote Desktop Services was updated to support both the Session Host (previously the Terminal Server sessions) and new support for VDI instances. One of the areas that are commonly discussed in VDI, which Brian was also discussing with us, is an important decision in the choice for pooled vs personal virtual desktops (PVD). I think that the scenarios for pooled are pretty much the same as the scenarios for Remote Desktops Services Session Host (previously Terminal Server). I also think that pooled generally isnt as good as RDS - but I do like PVD. Heres why.
Pooled VDI can be expensive and painful. Session Host actually does a LOT better in the exact same scenarios as pooled VDI. Why?
Session Host servers are (usually) centrally managed. That means they can be updated like any other server and downtime managed appropriately. The tools required to update those servers are the same tools as you update your clients with, like the System Center family of tools. This means you dont have to think about how you manage that infrastructure separately to VDI infrastructure. With Session Host, you also get at least 2:1 user scale over VDI and as high as 5:1 scale - so that means the CapEx and OpEx is much lower too and now that we have included App-V into the RDS CAL it means that app issues that previously affected density and compatibility are largely solved.
Pooled VDI typically utilizes a single master image and differencing disks linked from the master. These are then snapshotted back to the original state after the user logs off. It also means you absolutely must have good user state management and application management too. The promise though for it is that by updating the one single master image, you wont need management tools. The problem though is that it ignores a significant fact. It assumes that its the only technology deployed! The reality is that businesses will continue to use rich desktops and server infrastructure in combination with VDI and Sessions - that means management is still relevant except in this pooled model, you have to manage the pooled VDI separately to the way you manage your desktops, laptops and servers. That means pooled VDI generally does not integrate into your existing management tooling which by extension means extra work for just another delivery model for Windows desktops.
That said, Microsoft can support a pooled solution for VDI, though it really doesnt make a lot of good sense when Session host does so much better for the majority of instances and is cheaper in just about every way.
What you will see great support for from Microsoft in Windows Server 2008 R2 is for PVD. Our provisioning works really well here with SCVMM. It integrates nicely with Active Directory.
The scenarios are also clearly split out from RDS Session hosts too. Typically users requiring a PVD, are knowledge workers that requires high levels of personalization and isolation, and in some cases administrative access - which essentially delivers an experience akin to a physically installed desktop or laptop. Note that these are the very things that Pooled doesnt do well also!
On the upside for choosing PVD, is that it integrates into your current management infrastructure. That means any updates you send out, apply equally to your desktops, laptops and VDI instances. By extension that means leveraging your current single point of infrastructure management and therefore reduced TCO.
What this means
Microsoft does a really strong integrated solution with the VDI Suite delivered on the base platform of Windows Server 2008 R2 and Windows 7 to support a variety of use cases and scenarios that are better delivered with a combination of PVD and Session Host, rather than PVD and Pooled.
Session Host is cheaper to acquire and cheaper to manage than pooled and for the use cases that require higher levels of personalization and isolation you can add VDI instances and support the whole thing through the same connection broker, web access, protocol and gateway - and the user gets the right experience you give them, sessions or VDI desktops through that same single delivery infrastructure. Best integrated and managed solution at the best price.
Thats pretty compelling dont you think?
Now better get back to the filming...
Stop Press!: Update: Brian just said that he has already coined a term for this. Its what he calls the Maddens Paradox. I think that may mean he agrees :)