Friday, November 23, 2012

My VMware VCAP5-DCD exam advice: don't study for the exam

I passed the VCAP5-DCD (that's an acronym for VMware Certified Advanced Professional - Data Center Design)! To be honest I didn't study and had no sleep, which makes it similar to my first year of college. At college, I even got the Dean's Commendation for High Achievement! The achievement was for my high marks, not for my sleeping. Anyway, I've never been worried about whether I would fail an exam. Like most college exams, the result was determined before I walked in. The exam just showed me the result.

And that result was a PASS!

Everyone's learning style is different, so what works for me may not be relevant to your style of learning. But my advice is, don't study for the exam. Instead, focus on becoming a better designer. The VCAP5-DCD tests your application of knowledge, and you won't learn that from memorizing the content on the exam blueprint. The blueprint isn't a list of topics to study, it's a list of skills and abilities you should have. Rote memorization will help you pass the VCP5, practicing administration tasks will help you pass the VCAP5-DCA, but only design ability will help you pass the DCD exam.

What are these abilities?

You need to be able to ask why and understand why. Let me give you an example.

Objective 3.5 states that you should be able to "Design a vApp catalog of appropriate VM offerings (e.g., templates, OVFs, vCO)." Anybody can open the vCenter client, make a new vApp, add some VMs and set the startup order. But have you developed an opinion on vApps? Do you understand their advantages, disadvantages and their limitations? Which limitations have stopped VMware from packaging their own applications as vApps? Would any of these limitations apply to an application your company is developing? What application would you most like to see as a vApp? What application can't you believe isn't already a vApp? Instead of learning about vApps, the more helpful skill to learn is to ask why something is the case.

Pick any skill listed on the blueprint, say, storage design. You probably know what the different types of multi-pathing are. Why would you use one or the other? If there are Microsoft clusters in your environment, how does that affect which method of multi-pathing you use?

Being ready

If you can whiteboard a VMware design and explain the why behind every box and line you draw, you're probably ready. Try whiteboarding the following scenarios.
  • A small customer wants the cheapest implementation required to support high-availability
  • A large customer wants a solution that has no single point of failure.
  • That large customer just acquired the small customer. Design the migration strategy.
  • Remove one of the lines between storage and compute. What is the implication of this?

Probably a little too simple. But give it a go: explain what the red double-headed arrow
between the public cloud and private cloud is. How does it work?

(Note: Any similarity to an exam question living or dead is purely coincidental. I agreed to an NDA so I'm not disclosing anything other than the fact I signed an NDA, which isn't covered by my NDA!)

You don't even need to have experience whiteboarding in front of a client. Try whiteboarding in front of somebody who knows nothing about VMware, or even enterprise IT! I've found that some of the trickiest questions I've got have been from beginners.

Exam quirks

With most other IT exams, you can skip between questions. In the VCAP5-DCD, you can only go forward. There's no ability to flag questions and return to them later. Consider this a blessing: once you've answered the question, you're locked in! You'll only need to focus on the question at hand. Control the things you can control and don't worry about the rest.


I can't recommend you anything that will help pass the exam, because I didn't revise or study for it. However, I can recommend some resources that can help you become a better designer.

  • vBrownbags are free regular online meetings run by experienced VMware architects. If you want to know how experienced designers and architects think, watch some of these.
  • The Feynmann technique involves pretending to teach the idea to a new student. This forces you to understand the concept which should make you a better designer (and consultant).
  • Download the products and use them. Don't just do the usual VCP style labs: go off the rails! What happens to a VM when you power the destination host off during a VMotion? Do you understand what happened? If not, read up on VMotion! When should you stop reading? When you can explain it to someone who doesn't know anything about VMotion! Don't be afraid to go off-topic.
Anyway, I thought that would be the last VMware exam for me, but VMware have just VCP-Cloud and VCAP-CID. Time to book some more exams. The certification treadmill never ends!

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