Back in my college days, I shared an apartment with a few other people. One night, I was sitting in my room in front of my PC, staring at the keyboard, trying to figure out how to complete a project for my COBOL class (yes, I’m that old).
All of a sudden, I noticed some of the letters on my keyboard have been rearranged to spell something inappropriate 🙂 As I asked my roommates who was messing with my keyboard, they starting laughing because they’d done that over a month ago and completely forgotten about it.
I never look at my keyboard. I know that the letters F and J have little bumps on them so that my fingers are always on the correct letters. Every keyboard I use is consistent, always the same.
What would happen if the letters were rearranged? It’d be complete chaos for me. Instead of typing 85 words a minute, I would be lucky to type 5.
Consistency is critical to productivity and having a good user experience.
When we use our desktop PCs with local applications, consistency is a given, because we know we’re the only ones that can make changes. So, there is a very high likelihood that how things function and appear one day will be the same on the next.
But XenApp is different.
XenApp can send me to a completely different server for Microsoft Visio. Will my Citrix stencils be there? If I access Microsoft Outlook, will my signature be there? Will my custom dictionary be correct? Will the app have the right plugins? Will the screens be configured exactly as I left them?
For the sake of argument, let’s say you can guarantee that all of the XenApp servers hosting the same set of applications are installed and configured identically. What will you do after users start accessing the server?
Everything a user does will slowly add fluctuations into the configuration, until one day–BAM!–the app won’t load or a plugin fails. All of these minor fluctuations add up much more quickly than when compared to a traditional PC because instead of a single user accessing the PC for months, a XenApp server will host thousands of users in a matter of days.
This is why we require lifetime server consistency for XenApp, which is our next best practice.
XenApp Best Practice #3: Servers delivering the same set of applications must maintain configuration consistency throughout their life.