Thoughts on the VCAP-DTD

6858.strip So last night I wrote (and passed! YAY!) my VCAP-DTD exam. I figured it may be worthwhile to put down some thoughts on the exam as it may be different than others since I was also part of the team that actually created it. One of the first things to understand is how an exam like this gets created.

The number of people involved is rather impressive but I do believe it results in a fair but tough certification. The biggest challenge with an exam like this is that it can age faster than technological change (which definitely happened in this case). So any certification we create is done by following a few steps. The first is figuring out who the certification is targeted for. Is it for a new person to a product (VCA) or the ultimate expert (VCDX level). We call this the minimally qualified candidate. Don’t think of them as the top of the certification scale (the person who gets perfect) but rather the person who can just pass.

Once that is done we determine what is “fair game” for the exam. This is basically what the exam will focus on and from this the Blueprint gets created (and eventually released). Sometimes the time between the Blueprint creation and question creation can be quite large so we always re-evaluate the Blueprint to see if things need to be updated or change. Since we often know what will be included in the next upcoming release, we can account for it but what might be released 2 or 3 versions down is hard to predict (think dot releases so in View’s case 5.0, 5.1, 5.2 and 5.3). In View’s case, there were some significant changes between 5.0, 5.1 and 5.2. We knew of the 5.0 and 5.1 changes when writing the exam but couldn’t include anything beyond 5.1 because it would have been a significant time before that was included in the product.

So questions are written based on what the Blueprint covers. For Design exams this includes some of those Visio-like design questions along with mix-and-match questions and (as I call them) multi-guess questions. The Visio-like questions are the most challenging to make because you want to make sure that the question is narrow enough to help people design it without necessarily leading people to the answer. Once these are created, a beta exam is created and run for a period of time, usually about 4-6 weeks.

The results of the beta are passed on to a psychometrician, who would then go through the results and highlight questions that didn’t do well. The results of these are reviewed with a team to determine whether the question is to be kept or not. Once that is done, the question forms are finalized and then released as a final exam for the public to go and do.

So why mention all this? I had, honestly, forgotten how far back we had done the Design question writing in regards to the VCAP-DTD. Last night when I was doing the exam I was racking my brain as to when we lifted the initial cluster limit for NFS (5.1) and for VMFS (5.2) as that has an impact on potential designs (Visio-like). This is one of the advantages to the course that can definitely help prepare someone for this exam, the VMware View Design Best Practises 5.x. The course is also part of the VMware View Fast Track 5.1. If you didn’t start your desktop virtualization design career until Horizon View 5.2 or 5.3, then that could be problematic. Oddly enough, I had just taught the Fast Track the week before and got reminded of all the little bits that I’d have to remember for the exam itself.

The other piece that helped me was the interactive simulation. This simulation gave me a better feel of the Visio-like tool. I suspect that also might have been my downfall previously, particularly in regards to the connectors and not getting those connected right.

When it comes to the exam (200 minutes in length plus 10 minutes for the survey, thus totaling 3 and a half hours), taking your time and reading the question makes a huge difference. I did the beta and failed it by a few points, something I attributed to poor exam habits (i.e., rushing through the exam and not fully reading the questions). One advantage with the public version over the beta is that I now could go back and review those Visio-like questions. There was, previously, a bug that would erase those designs if you went back (which has since been fixed). For things to focus on, well the Blueprint helps with that. I would suggest that if you take either class, make sure you learn those formulas we provide for IOPs (IO per second) and bandwidth (network and storage throughputs). You’ll need them and the public version does now include a calculator to help with those calculations (something that was missing in the beta).

So when doing this exam take your time and pace yourself well. Read the questions CAREFULLY! And make sure you know which version we talk about. When it’s View 5.0 or 5 then it’s 5.0. If it is View 5.1 or 5.x then it’s 5.1. As always watch your time but don’t obsess over it. You can go back and review. I had about 45 min left over for review (I didn’t use it because I’m always worried about changing things from the right to the wrong answer).

Good luck!

 

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