In the last post of my series about Microsoft VDI I discussed the VDI software that Microsoft already offers today. In this article, I will give a short overview of two new technologies that might turn out to be vital for the adoption of VDI in Microsoft environments: RemoteFX and Dynamic Memory for Hyper-V.

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RemoteFX is a technology that Microsoft acquired two years ago with Calista Technologies. It is an enhancement of RDS (Remote Desktop Services) that will be delivered with Windows Server 2008 R2 SP1 (no official release date yet, probably not earlier than Q4 2010). Essentially, RemoteFX will offer support for the following technologies in a Remote Desktop environment (session host and VDI):

  • Windows Aero
  • Full-motion video
  • Silverlight animations
  • 3D applications

Obviously RemoteFX could be essential for VDI because one of the major drawbacks of desktop virtualization is that the user experience of Remote Desktop is usually worse than on local PCs when it comes to graphics virtualization.

It is important to note that RemoteFX will provide only the same user experience on a local desktop when connecting over a LAN to the remote desktop. I will probably say more about this topic once Windows Server 2008 R2 SP1 has been released. In the mean time you should have a look at this excellent user experience test over at brianmadden.

Dynamic Memory for Hyper-V

Dynamic Memory for Hyper-V is another new feature that will be delivered with Windows Server 2008 R2 SP1. Dynamic Memory for Hyper-V is an important technology for VDI because it will enable greater virtual machine density.

Even though the technology behind Dynamic Memory is somewhat complicated, from an admin's point of view this feature appears to be fairly simple. (Note: The original article has linked to has been removed. I will link to some more detailed descriptions of Dynamic Memory in one of my next posts.)

If you understood the concept of dynamic disks in virtual machines, you already have a basic understanding of how Dynamic Memory works. You can either assign a fixed amount of memory to a VM or use the hot-add capabilities of the guest OS to increase memory dynamically during runtime. If you work with Dynamic Memory you can assign a minimum amount of memory to the VM, which will eventually reach the maximum RAM you configured for the VM. Like with dynamic growing virtual disks this means that you overcommit resources.

Please note that other vendors of virtualization software use the term "memory overcommitment" in a different sense. For a short comparison between Microsoft Dynamic Memory and VMware's memory-overcommit methodology please check out this article.

Dynamic Memory for Hyper-V will probably not be used very often for server virtualization. Like dynamic disks they have a negative effect on performance, and the risk that a server does not get all the memory it needs to perform at an optimum level is too high.

However, since performance is less important for desktops the negative impact of Dynamic Memory on the computational speed will be less significant for VDI. Moreover, increasing the virtual machine density is essential for VDI because the number of virtual machines running on specific Hyper-V system has to be much bigger than with virtualized server to be competitive with cheap desktop hardware.

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Of course, all this wonderful VDI technology comes at a price. Unfortunately, it is not enough to buy Windows Server 2008 R2 or one of the VDI suites. In my next post I will cover Microsoft's VDI licensing.


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