Handling sub-optimal design decisions before the VCDX defense

So you’re design got accepted for a defense, that’s great! While preparing you find out there are few things you want to change, a few “holes” in the design. Maybe it’s questionable design decisions, maybe it’s just adjustments needed or maybe typos you missed. That’s OK, relax, no design is perfect and it’s OK to have second thoughts on your design decisions, just like with a customer you need to make the required adjustments and present it, right? Well, not so fast, this is after all your VCDX on the line, too many things that you will consider wrong will make it very hard for you to defend in front of the panel. In our design we had from all the goodies, sub optimal design decisions, stupid decisions and typos. So what to do? Well I got a lot of good advice from many top VCDX’s but one I got from Michael Webster aka @vcdxnz001 and Mark Achtemichuk aka @vmMarkA were right on the mark (mark on the mark, get it?). What they told me is to prepare for this with an alternate design choice but dont forget to explain your initial reasoning for the original decision. I would just add that it would be highly advised to think hard and try defending your original decisions as much as you can, you want to minimize the amount of faults in your defense, maybe you can tie it to business requirements or constraints then it might make more sense. Remember, If you rely on a constraint as a crutch you also need to be able to explain what you would have done if you hadn’t had it (words of wisdom by Joe Silvagi aka @VMPrime) . This can be approached in several ways:
1. Keep the original decision and defend it but prepare a backup slide in case you get asked about it. I would say that this is for decisions that can make sense I’m the business contaxt mostly.
2. Call out the issue before you get asked, explain why you made this decision and explain that in hindsight it should have been something else, important to note that you want to minimize the time it you spend on it in the defense otherwise you will enter that famous rabbit hole from Alice in Wonderland but with out the wonder, just wasted time you can score on other things.
3. Change the decision putting less emphasis on the original decision, this is when the decision really doesn’t make sense.

Either way as long as you can explain the thought process behind what you do and can show how you correct any imperfections you can actually show your mastery of design even better. Be honest and don’t try to defend what you can’t.
From my own experience, at the end it turned out well.
This was a real pain for me during those couple of months before the defense, I remember I had nightmares of the panel laughing in my face and kicking me out because of a few decisions we made, but if you take a chill pill and think it through you will find your way to defend and try to focus on to the areas you are stronger and remember, practice, practice, practice .



  1. says

    Hi Niran, Great advice. I’m glad I could help. I remember my defence pretty clearly. I was sitting at VMware campus in the Cafe about 15 minutes before it was due to start and I found an error in my design. It was one of those moments where I can’t believe I wrote that bit. Anyway, during my defence when we got to that topic and we were discussing an aspect of it, in response to a panelist question, I just pointed out the error and what it should have been and why. The design still worked with it the way it was written, but it could have been better, and there were some gotchas with the setting as it was. Mistakes like this can easily be defended. If your design gets through to the panel in the first place the reviewers believe you have a material chance of passing and defending it, so it must be ok. Then you just have to step up on the day. No design is perfect, but you need to know your imperfections.

    • niranec says

      Thanks Michael, that was a very good advice that i implemented in my defense prep. Amazing how 1 good advice can make a difference.


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