Virtual Desktop Infrastructure (VDI)

Virtual Desktop Infrastructure (VDI) is a subject that is becoming more and more popular but it can be quite a tricky concept to newcomers, my aim here is to give some clarification and information on the topic!

What is VDI?

VDI is the younger, not as cool cousin of server virtualization and the bigger, better brother of Terminal Services (TS) 🙂

Rather than running the desktop instances on local machines, they are held on servers in the datacenter and each user accesses them centrally. However, unlike Terminal Services “each user gets access to their personal desktop from any authorized device, thereby improving desktop flexibility”.

The VDI FAQ from Microsoft offers a good overview of VDI as a technology-download the PDF here.

What’s the point?

Storing desktop images on central servers can have many benefits:

Management: VDI gives you true central management of users desktops and true control over what is/isn’t installed on them and, as I’m sure you know, that can be a real issue in corporates today! You can manage a single instance of the OS no matter how many people are using it-vastly reducing management time & costs.

OS deployment: VDI can make the provisioning of new desktops much quicker than usual and can also enable organizations to test/adopt new Operating Systems in a much easier fashion. One big scenario where I see this being particularly useful:

     Testing multiple Operating Systems: Say you have a number of users that are testing various different desktop OS’s such as XP, Red Hat Linux and Windows 7. Currently you would need to either:

  • provide the users with multiple machines, all separately configured and offering their own security concerns.


  • have users multi-booting their machines-again presenting it’s own set of problems around hardware with people needing more RAM etc

Alternatively you could have one image of each OS in the Datacenter and users can access them as needed-with much less hassle 🙂

You can also keep a “library” of images for different situations that can be deployed at the drop of a hat!

Security: Again, the central management aspect comes in to play allowing you to block external devices and prevent copying of data from the image to a local device-a great way of preventing data leakage.


Despite all the benefits above there are, as with everything, downsides and negatives too.

  • VDI really isn’t suitable for media intensive tasks
  • Doesn’t suit mobile working as it requires a constant connection to the corporate network.
  • Negative feedback from users

The last point is perhaps the most important for companies to consider-all the streamlined management processes and more flexible admin environments don’t really count for anything if the workforce is unhappy. Certainly I would hate to work in a VDI infrastructure (or Terminal Service/Citrix) as I install and use a LOT of applications that wouldn’t be part of a corporate standard such as Office 2010, CCleaner,TweetDeck, numerous Outlook addins, Groove, OneNote (and I don’t know how many more!); also I often run things that require admin rights on the  machine. In a VDI environment I would have to go through the hassle of getting these added to an image which would be just for me-so I might as well have a standard desktop. The alternative is that I couldn’t use the applications which would reduce my produtivity as well as my happiness as a worker-2 things that a company definitely doesnn’t want to be happening 🙂

What VDI can do to some users!
What VDI can do to some users!

An actual comment from a user over at Tech Republic:

“the fact that I can take my work anywhere doesn’t matter to me if I can’t install what I need when I need it”

How is it licensed?

Microsoft’s VDI licensing structure is comprised of 2 parts:

  • Vista/Virtual Enterprise Centralised Desktop (VECD)
  • Microsoft VDI Suite Standard/Premium

VECD allows you to licence virtual copies of Microsoft’s desktop OS’s in a VDI environment and offers the following:

  • Ability to run a copy of Windows in a datacenter
  • Rights to move virtual machines between servers for increased reliability
  • Unlimited backup of virtual machines
  • Ability to access up to 4 running VM instances per device.
  • Rights to access corporate desktops from home for a user that has already been licensed at work
  • Availability of volume licensing keys, such as KMS (Key Management Service) / MAK (Multiple Activation Keys)
  • How is VECD licensed?

    VECD is a monthly subscription per device licence which comes in 2 flavours:

    • VECD (for users without SA)
    • VECD for SA (for users with SA)

    They offer the same functionality, it’s just the VECD for SA is available at a reduced cost as a thank you to current SA customers 🙂 I’ve not got UK pricing to hand but the pricing on the MS website is:

  • VECD (for users without SA) = $110 per device per year
  • VECD for SA (for users with SA) = $23 per device per year
  • VECD is required for any VDI solution that will be running Windows Operating Systems, regardless of the the BDI technology provider (VMWare, Citrix etc).

    Microsoft VDI Suite:

    This is a new addition to the world of licensing, having been announced at the WorldWide Partner Conference (WPC) last week. While MS have had the technologies to provide a cohesive, efficient and secure VDI environmentfor quite some time now, it has been hard for customers to know what products they need and which things fit together. The VDI Suites are simply a collection of technologies at a reduced price, and they are:

  • Hyper-V Server
  • System Center Virtual Machine Manager (VMM)
  • System Center Configuration  Manager (SCCM)
  • System Center Operations Manager (SCOM)
  • Remote Desktop Services (RDS) CAL (formerly Terminal Service CAL)
  • Microsoft Desktop Optimization Pack (MDOP)
  • For a fuller more in depth look at the VDI Suites, including expected pricing, please see my other blog post here.

    A 100 device company looking to implement VDI would need the following:

    100 x VECD @ $110/£67 per device per year = £6700

    100 x VDI Suite @ $21/£13 per device per year = £1300

    So £8000* per year to run a Microsoft VDI infrastructure with what is fast becoming a truly top-notch hypervisor as well as leading class management software-sounds pretty good to me 🙂

    *The £ prices above were attained by putting the $ prices through , but the final pricing may well be different!

    I hope that has gone some way to informing newcomers as to what VDI is as a concept and also helping people who know the technology make sense of the licensing. As always, I’m happy for feedback & comments 🙂

    5 Replies to “Virtual Desktop Infrastructure (VDI)”

    1. Good summary of the good/bad wth VDI. However, there are many solutions coming to market now that will deliver true personalization for VDI, and will enable user-installed applications and plug-ins to standard apps, such as those you mentioned, to exist for each individual user. They won’t have to be added to the base image so the Gold image can remain clean, and yet they will persist through any base image updates.

      This concept – called desktop layering or desktop compositing – was one of the big topics during Briforum this week in Chicago. See

      Tom Rose
      Unidesk CMO

    2. Microsoft seems determined to drag us (kicking and screaming) into a subscription-based model, and I for one am having a tough time signing on. 8K per year, every year, year after year, seems like A LOT of money to spend for licensing on 100 desktops, considering what we’re used to paying for PCs — and with the old XP OEM-based licensing WE were in charge of the upgrade cycle.

      Can you imagine if Microsoft’s scheme had come to pass three years ago, and companies with tightened IT budgets were having to shell out 8K per 100 desktops just to keep using their systems legally? Many companies I talk to have pushed out their refresh cycles and are getting another year (or 2, or more) out of existing desktops, hoping budget situations improve in the future. I haven’t seen a single honest ROI where this makes such a compelling case that going to the subscription model makes it worthwhile to give up control.

    3. Hi John,
      Thanks for the comment.
      I don’t think MS are particularly pushing people towards subscription models, they offer a pretty balanced mix between subscription and perpetual programs. What software are you getting for your 8K a year, as that to me, sounds like a pretty good deal!
      The subscription model has a number of benefits for customers including the ability to reduce the number of licences and a single yearly payment. Also, you are still in control of your upgrade cycle; although you are entitled to run the latest version of software…you are not obliged/forced to do so.

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