The Desktop Transformation Assessment (DTA) forms an integral part of the overall Desktop Transformation Model (DTM) by providing clear guidance on how to turn “Wow” into “How”.  During this series of blog posts, I’m discussing the seven key phases that make up the DTA:

  1. Define Business priorities
  2. Application Assessment
  3. User Segmentation
  4. Capabilities Assessment
  5. High-Level Design
  6. Desktop Transformation Roadmap
  7. High-Level project plan

In my last post, I explained how important it is to define the key business priorities behind the desktop transformation initiative.  Once these have been identified, what’s the next step?

It’s time to  perform an application assessment that reviews the entire application estate and determines the most appropriate delivery mechanism(s) for each application – installed, streamed, hosted or VM hosted.  For large-scale projects this may seem like a daunting task.  Fortunately, Citrix Ready has created a DTM site that lists a variety of third-party products that can help to simplify and accelerate this activity.

To help you with this task, I’ve broken down the application assessment into three main sections and provided some tips on what to look out for:

  1. Compatibility Requirements. Desktop transformation typically involves a change of operating system (e.g. Windows XP x86 to Windows 7 x64) and/or application delivery model (e.g. installed to streamed).  Therefore, the compatibility of each application should be assessed so that an appropriate desktop and application delivery model can be selected.  Third-party tools can be leveraged to quickly assess application compatibility against different operating systems, architectures (i.e. x86 and x64) and application delivery models.
  2. Infrastructure Requirements.Infrastructure requirements must be established for each application so that an appropriate delivery model can be selected and sufficient resources allocated.  To gather this information, a third-party monitoring tool is typically installed across a representative sub-section of the business.  Try to spend as much time collecting data as possible as this will help to improve accuracy.  Also, try and monitor the infrastructure during periods of peak activity, such as quarter-end or busy sales periods.  At a minimum, ensure that the following application characteristics are identified:
    • Performance. What are the performance characteristics of the application, for example processor, memory, graphics, network, disk space and disk I/O?  For each characteristic, determine the average and maximum values.
    • Dependencies. How do the applications interact with one another?  If any of the applications require a close level of interaction, beyond file association, it may become necessary to co-locate them within the same image or application streaming profile.  Do the applications require any peripheral devices?  If so, check that the peripherals are compatible with the selected delivery model.
    • Architecture. How do the different components of the application fit together?  Locating desktops in close proximity to the backend application servers will typically help to improve performance.
  3. Business Requirements.Business requirements are normally captured through interviews or questionnaires and should include the following topics:
    • Redundancy. The importance of the application to the business will dictate the level or redundancy required, including additional desktop infrastructure and DR capability.
    • Offline Access. Establish whether the application will be required offline by travelling employees or as a fallback option in case of DR.
    • Update Frequency. The frequency of updates may impact the application delivery model selected.  For example, application streaming can be used to reduce the number of master images that need to be updated.
    • Future Changes. Identify any planned changes to the application estate so they can be factored in to the desktop transformation project.  This may include new applications, application consolidation and application upgrades.

I’m sure it’s no surprise that the application assessment will generate a considerable amount of data. I’ve found the easiest way to analyze this information is to use a spreadsheet so that different requirements can be easily compared and grouped together.  I normally use a table with the following columns:

Application, Version, Users/Job Role, Architecture, Processor (Average & Maximum), Memory (Average & Maximum), Graphics (Average & Maximum), Disk Space (Average & Maximum), Disk I/O (Average & Maximum), Dependencies, Compatibility, Update Frequency, Redundancy, Offline, Potential Application Delivery Model

When it comes to assigning an application delivery model, it’s a good idea to have a defined strategy in place, for example:

Preference Application Delivery Model
1 Stream to XenDesktop
2 Stream to XenApp and deliver as hosted application within XenDesktop
3 Install to XenApp and deliver as hosted application within XenDesktop
4 Install to XenDesktop

Hopefully this outline will help guide you through the application assessment phase of the DTA.  Check back soon for details on the next step in the DTA – User Segmentation.

Andy Baker – Architect
Worldwide Consulting
Desktop & Apps Team
Virtual Desktop Handbook
Project Accelerator