VCAP5-DCD Exam prep

A number of people have shown an interest in how I prepared for the VCAP5-DCD exam (there’s also been interest in how I prepared for the DCA exam, so I may do a post on that at a later date).

It is a difficult exam to revise for, the biggest problem being that there is nowhere to practice some of the new question formats which are introduced in the DCD exam. I’m talking about the Drag-and-Drop and the Design Tool (also referred to as Visio-style) questions.

I was fortunate to find this blog post about the exam format, a few days before the exam, which helped. It’s very, very helpful, and I say a huge thank you to the author for sharing that experience.

My actual preparation started with the blueprint, and then I searched for study guides. I found the following ones the most helpful:

Virten.Net – Florian Grehl
Virtually Hyper
and the vBrownBag APAC sessions, collated by Nick Marshall, which I downloaded to my phone and listened to as podcasts while commuting. You don’t lose a lot by not seeing the slides.

Books were also a key part of my revision – the study guides don’t go into as much detail, but the books can be a bit overwhelming. I think it took me several *months* to get through the Clustering Deep Dive!

I was fortunate to be given a copy of VCAP5-DCD Official Cert Guide book – Paul McSharry when attending our company conference in Atlanta a few weeks back. This was a straightforward read, helpful on the business requirements / design objectives, for someone like myself – coming from an Engineer point of view rather than Architecture.

While I don’t own a copy of VMware vSphere Design 2nd Edition – Forbes Guthrie I was able to have a thumb through one and think I might be adding it to my (virtual) bookshelf for my work towards VCDX. It looked to be very useful for the VCAP5-DCD exam anyway.

The toughest of the books I read was Vmware vSphere 5.1 Clustering Deep Dive – Epping/Denneman. As I mentioned above, this took me a long time to read through, and was very informative on DRS and HA. The best thing about having the ebook version was that I could pull out all the “Basic Design Principles” mentioned throughout the book, and have 4 pages of A4 that had key design concepts to remember.

Coming from an engineering perspective, one of the hardest things to get my head around was the business requirements, design methodology and architectural aspects of the exam. I spent a long time getting to grips with Requirements (Functional and Non-Functional), Constraints, Assumptions and Risks. This is really fundamental to passing this exam if you come from the same background as me. I can only recommend that you do as much reading around these terms as you can. There is a certain amount of overlap between them, which can depend on perspective, and the type of design you’re doing. I only started thinking about booking the exam when I felt confident about placing something into one of these categories without second guessing myself.

One other thing to make sure you do, is to watch the demo of the design tool. I would recommend watching it several times, so you’re more comfortable with it.

And so on to the exam itself…

I had 6 design tool question, I think something like 10 drag-and-drop questions, and the rest of the 100 were the single/multiple choice.

The first 2 questions were design tool ones, which was a real tough opening to the exam, but when I got stuck into the first one, I started to feel much more confident. In fact, I didn’t really have too much trouble with the design questions (although as you don’t see your detailed marking, I can’t guarantee how well I answered them!), but it was some of the drag-and-drop ones I found hardest.
Some were straightforward – 4 choices to drop on 4 options, but some had 7-8 choices, 7-8 options, and you could use the choices multiple times, or not at all. These were really difficult as you really did find yourself second-guessing whether an option could go in 2, 3 or maybe 4 places, then taking it out again, and so on.

This comes to another tip – don’t get bogged down. At some point you have to go with your best guess.

I had a PC crash just as I’d completed one of the design tool questions – I was wiggling an object to see if the links were connected ok, and the screen froze. I got the “A script on this page may be busy or may have stopped working” error, and eventually an application error. You can read more on my previous post, but I got up and running again on another PC, albeit with that question reset back to blank. Re-doing the question took a fraction of the time it took originally though.

The 15-20 mins per design tool question, which a number of people have suggested as a rule of thumb, seems to be a good idea. There were a couple that took nearly 20 mins, but some were much shorter – one I think was only about 5 minutes.

Another exam tip I would reiterate is to read the question before the supporting material. It really helps you to narrow down your reading of what is often excess material. There were a number of questions where you really did not need to read the supporting material whatsoever!

You can once again review the questions at the end of the exam. This was removed for a while due to problems with some answers being lost, but I was able to go back and check that my first few questions (done on the 1st PC) were still there.

Then all you have to do is hit “End Exam” and after a few seconds you get your results. All I saw was “Congratulations…” and I was out of the room!

Finally I’d like to thank all those who have contributed to the community, especially those I’ve linked to above. Without their help, this exam would have been a lot tougher to revise for. And good luck to anyone reading this, I hope I’ve helped you.

 

 

 

 

 

 

 

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VCAP5-DCD exam

I travelled up to Leeds today for my first attempt on the VCAP5-DCD.

My last visit to Global Knowledge was for the VCAP5-DCA, and I’d intended to go up on the train, only to get to my local station to hear that the train I wanted had been cancelled. The next one would have arrived too late, so I had to high-tail it back home and jump in the car.

This time, I turned on the TV for the local news to announce that the M1 Northbound was closed near Barnsley, and would be shut for at least the next hour. I’d intended to get the train anyway, but this meant no fallback situation of driving, so I dashed to the station to get the half-hour earlier train, to give me a bit more scope for problems!

Being this early meant of course that there were no problems so I was at GK an hour before the exam start time! I had time for a little more revision, and a drink of water, plus my pre-exam banana (one of the hints I picked up from an exam blog).

Checking in to the exam took longer than usual – not sure why – but soon I was at the PC and going through the pre-exam survey.

Then on with the exam! I obviously can’t say much about it due to NDA, but my first 2 questions were the visio-style ones. Talk of a tough start! After a brief panic, I read the first one properly, and it seemed achievable, and so I continued.

About half-way through, I’d just about completed #3 or #4 of the visio-style questions and was giving all the objects a little wiggle to make sure things were connected properly when the PC froze up. After 30 secs or so it displayed the “A script on this page may be busy or may have stopped working” message, I clicked wait and then the screen updated again. Phew I thought, then it froze again. This time I also got “An application error has occurred”.

Great.

I put my hand up. No exam administrator running to my rescue.

I waved my arms around still nothing.

Eventually I knocked on the wall (I could hear them in the next room) and one of them came through. After about 10 mins I was up and running on another PC (apparently the camera system had frozen so it looked like we were all working away fine), but it had lost all the work on that question, so I had to repeat it.

I requested they contact VMware for extra time to make up for the lost time, and they did so (in the end I decided I didn’t need it, and would have had to stop so they could add the time. Was good to know that the option was there if I was running out of time though).

Anyway, the rest of the exam went without a hitch, although the multiple choice and drag&drop questions seemed to get harder, and I reached question 100 with 1h 15m remaining on the clock. I’m not one to go second guessing my self, so I just used the review page to make sure the first couple of visio-questions were intact, then hit the End Exam button.

I was delighted to see “Congratulations” on the page – I’ve no idea what else it said, as I was straight out of the room!

vcap5-dcd

So next step is the VCDX, but before that I have a stag night, a wedding, a honeymoon, a family holiday. Probably won’t even remember what a VM is after all that!

Oh and I’ll try and get another post out soon about which resources I found most useful in preparation for the exam.

VCAP5-DCD Prep – Active vs Passive discovery

I’ve not been able to find a good list of what are active, and what are passive discovery methods. It should seem obvious, but I have a recollection of an example question about it on someone’s website that confused the matter.

One of my confusion points is that the only definition I can find on the matter from VMware talks specifically about “application discovery and dependency mapping” via network discovery:

Effective application discovery and dependency mapping requires three primary methods:
• Active discovery—This method uses common network protocols to remotely query servers in the managed network and obtain supplementary CI data about network hosts. However, using just active discovery can place an unnecessary burden on the network. In addition, large segments of CI data don’t change all that often, making repeated realtime active discovery unnecessary for many. Furthermore, although active discovery uncovers detailed CI data about hosts and services, it doesn’t easily or directly provide information about how they relate to others. But active discovery doesn’t require agents, and delivers a wealth of solid CI data.
• Passive discovery—This method provides more of that relationship data. By connecting to core span or mirror ports on network switches and sampling network traffic, passive discovery can identify network hosts and
servers, their communications and connections, and what services and protocols are being exchanged at what time. Although another rich source of data, you need some additional capabilities to assemble this raw data
into actionable information.
• Discovery analytics—This third element complements the first two with the ability to perform deep-packet analysis of observed traffic, and to help establish the relationships between passively and actively discovered
entities. Analytics with rich data provides little benefit; the same holds true for active and passive discovery.

Together, active discovery, passive discovery, and discovery analytics deliver a hybrid approach to application discovery and dependency mapping—provides the most complete approach

My view on it (and am happy to be corrected if I’m wrong in this regard) is that Active discovery is where you go out an get information from the target systems directly, passive is where you collect it without you having to talk to the target systems yourself.

If something is already being collected to a separate database, then querying it is passive (as long as that querying is not going to affect the target system)

Passive Discovery

  • Port mirroring on a switch
  • VCenter performance stats database
  • Config management database
  • Project documentation
  • Any statistics already collected by an IT Management Framework
    (eg HP Openview)

Active Discovery

  • Network probing
  • Windows Perfmon
  • ESXTOP
  • VMware Capacity Planner

 

CSC TechCom 2014 over.

I’m just about over the jet-lag from last week – 3 nights is too short for a trip to the US, I’d just got over the time difference there when I had to set off back!

I had an exhausting but enjoyable time overall – the Tuesday and Wednesday I was on the go from 7.30am until around midnight!

The Monday, I set off from home at 5.30am to drive to Manchester Airport. I’d allowed 90 min to get there, so that I would be checking in 3 hours before the flight. As you’d expect, this was way too much time, and because I was so early I passed through the normal traffic jam spot of Mottram without even stopping! Unheard of!

The flight was bang on time, and a good selection of films, along with my kindle loaded with VCAP5-DCD revision materials, helped the 8.5 hour flight to pass relatively painlessly.

Baggage claim and immigration were cleared quite quickly, then it was a short-ish journey on the MARTA system to the Hyatt Regency hotel.

A quick check-in and dropping bags off and it was time to meet folks and head to the first general session. I can’t really discuss the content of the sessions on here, but they were of a high standard, and covered business direction and technical matters.

After the general session we headed to the exhibitors area, and had a buffet meal, a drink or two, and toured the stands. I headed to bed about 9pm, having been up for 21 hours at that point. As it happened, the latest episode of “24” had just started, so I watched that and called it a night!

VCAP5-DCD Study – NFR or Constraint, continued

Following on from yesterday’s post about Non-Functional Requirements vs Constraints, I think I’m a little clearer on this subject, but it appears that it’s not something you can define exactly. To an extent, it depends on the context of the project.

@greggrobertson5 put forward that Functional Requirements are the WHAT and Non-Functional Requirements are the HOW.

Following on from that, something like “must reuse existing hardware” is a NFR, but it is also a Constraint. Think of it as a Venn diagram where the circles for NFR and Constraint intersect, and items can fit into NFR or into C, or the intersection between them.

NFR-C

I also looked up NFR on Wikipedia (yeah, I know, the last resort of the clueless!) and was interested to see it stated “Other terms for non-functional requirements are ‘constraints’ “

VCAP5-DCD Study – NonFunctional Requirement or Constraint

Something I’ve been really struggling with in my DCD prep is understanding how to determine what are Requirements, Risks, Constraints and Assumptions.

Specifically, how do you determine Non-Functional Requirements from Constraints.

For example, if a project states that the existing kit should be re-used, is that an NFR or a Constraint?

We are required to re-use the kit, but it constrains the design.

I asked TheSaffaGeek about this via twitter (@GreggRobertson5) and he directed me to this discussion. This helped somewhat, although I’m still a little fuzzy on the matter.

Jason Langer’s document package includes the PDF “Functional versus Non-Functional Requirements” which lists the following as Functional Requirements:

  • Business Rules
  • Transaction corrections, adjustments,cancellations
  • Administrative functions
  • Authentication
  • Authorization –functions user is delegated to perform
  • Audit Tracking
  • External Interfaces
  • Certification Requirements
  • Reporting Requirements
  • Historical Data
  • Legal or Regulatory Requirements

and the following as Non-Functional Requirements:

  • Performance – Response Time, Throughput, Utilization, Static Volumetric
  • Scalability
  • Capacity
  • Availability
  • Reliability
  • Recoverability
  • Maintainability
  • Serviceability
  • Security
  • Regulatory
  • Manageability
  • Environmental
  • Data Integrity
  • Usability
  • Interoperability

So to me, that would make it pretty clear that “Re-use Existing Hardware” is neither a Functional, nor a Non-Functional Requirement, but a Constraint.