The promise of VDI: Are we there yet?
Virtual-desktop infrastructure promises to be a foundational technology for cloud. If so, it still needs improvement, says John Webster.
My wife works for our local school department as an IT support specialist assigned to the town's largest elementary school. Like many U.S. elementary schools, kids and teachers use a variety of personal computing devices, including PCs, notebooks, and now tablets. (Everyone wants to use these 'cause they're way cool.)
Keeping this veritable Noah's ark full of computing animals happy is more than a full-time job. There are more than 400 of them and they have quirks that give most of them unique personalities. If she comes home and tells me she had time for lunch, I know it was a relatively good day.
I don't know if the town's IT department has heard of virtual-desktop infrastructure (VDI). They probably have, and may even have plans to roll it out. I don't know and maybe I don't want to know because I privately worry that my wife could lose her job if they do.
VDI has gotten the attention of IT administrators across industry segments as a way to impose order over the chaotic state that now defines many enterprise desktop environments that are PC-based. It offers IT administrators an opportunity to redesign the way they deliver applications to users in a consistent and centralized way -- and one that encompasses the wireless desktop. VDI has also emerged as a foundational technology for cloud-based IT services delivery models. At least that's the promise.
The reality to date has often been less appealing. Typically, IT administrators are forced to make a choice between the needs of their users and efficiency. In the case of my wife's school, teachers for example have grown accustomed to teaching with a set of applications that are grade-level specific and sometime tailored to the needs of particular students -- like children with learning disabilities. VDI can offer the school's IT administrators a high degree of standardization (good for them) but are permitted few if any opportunities for customization (not so good for teachers and kids).
A new approach is emerging that gives both types of users their needed customization in an efficient management environment. It is known variously as "layering," "persona management," or "VDI image management." IT administrators manage multiple OS and applications layers as a centralized process while delivering personalization for users.
Storage plays a critical role. It's been the biggest cost issue for most VDI implementations, and can exceed $500 per user, sometimes more. Therefore, the race is on among vendors to bring down this cost. Fully provisioned desktops typically require their own capacity, which is an inefficient way to store desktop images that may contain 90 percent to 99 percent of the same data. A storage system feature found in modern storage architectures supports the creation of writeable copies (clones) allowing administrators to provision virtual desktops while eliminating data duplication and thus drastically reducing storage capacity.
Storage also plays a critical role in layering which separates the VDI "stack" into manageable groupings of objects -- OSes, applications, and user interfaces. From a storage perspective, the OS and application layers can be designated as read-only, while the customizable user interface objects are writable. This solves two problems with the VDI experience to date. For users, unique, personalized stacks may be put together that address their need for customized applications and potentially give them the use of their platform of choice. (Think tablet here.) Perhaps even more importantly for IT administrators, the OS and application layers in these stacks are shared among multiple users. As a result, updates and patches to the underlying layer are automatically applied to all users who access that layer.
Several companies have begun to create layers for VDI, providing the ability to create custom stacks of applications. Others have begun addressing the need to personalize a VDI environment without requiring fully persistent desktops. Both VMware and Citrix encompass "user persona" features within their latest VDI offerings. Smaller players include AppSense, Moka5, Unidesk, and Wanova. Now, should I tell my wife's boss about them?