VCDX – Pressure Testing

As part of my VCDX mentoring process, I like to conduct “Pressure Testing” sessions to see how the VCDX Candidate reacts to rapid-fire questions, measuring how quickly they can access information and respond intelligently.

List of articles in my VCDX Deep-Dive series (more than 70 posts)

People who are not used to operating under pressure can react strangely – for example, blathering, long periods of silence, speak in mono-syllables, walk out of the room, etc.  As a VCDX Candidate, you need to make sure you can operate normally under pressure.  There is only one way to get used to it and that is to practice, practice, practice.  This is where Study Group and T-Skilling is invaluable.

It is very common, to go through a Pressure Test or VCDX Defence and later realise you knew the answer to a lot of the questions you could not answer when asked.  Without preparation, stress and pressure can disrupt your ability to think critically and analytically.

When you attend your actual VCDX Defence, you may not even get one of the questions that you prepared with, which is irrelevant.  What is important, is conditioning your mind to function under pressure, which will hopefully translate to you passing your VCDX Defence.

The “Pressure Test”

• A typical “Pressure Test” session will last for 30-60 minutes.
• With 4-5 questions per minute being asked.
• The questions should range through the entire VCDX blueprint or focus on a particular silo of weakness.
• Each technology silo will start with Basic questions, then move to Advanced and Expert content.
• You have 5-15 seconds to respond concisely and clearly.
• Answer length will vary depending upon the complexity of the question.

Response Strategies

• You clarify what is exactly being asked and respond with the answer (if you know).
• You know the answer and deliver the information within 5-15 seconds.
• You THINK you know the answer and respond accordingly, including how you would verify it.
• You can take an educated guess and reason it out on the whiteboard, including how you would verify it.
• You have no idea, but you know where to find the information.
• NEVER, EVER JUST SAY: “I do not know.”  You do score for knowing where to look.
• Watchdog Timer: when each question is asked, if you are talking for more than 15 seconds, ask yourself, “AM I BLATHERING?”, if “YES”, STOP TALKING!

Cadence of Speech

The VCDX Defence is time constrained, you are continually competing against the clock to demonstrate your skills to the panelists.  You need to increase the cadence of your speech to clearly and concisely deliver more information in the shortest time.

Example Pressure Test Question Sequence with vSphere 5.5 for vSphere High Availability & vSphere Fault Tolerance:

• BASIC – What vSphere feature allows a customer to protect a workload from failure? (Answer: vSphere High Availability)
• BASIC – What exactly does vSphere HA allow me to protect against? (Answer: VM against Host failure, OS failure and Application failure)
• BASIC – What other features of vSphere complement vSphere HA? (Answer: vSphere FT and vSphere DRS)
• ADVANCED – What component of ESXi is responsible for vSphere HA? (Answer: Fault Domain Manager – FDM)
• ADVANCED – What are the requirements for vSphere HA to protect against VM OS failure? (Answer: VMtools must be installed and VM Monitoring must be enabled)
• ADVANCED – How many 9s of availability does vSphere HA provide? (Answer: 99.9% and vSphere FT 99.99%)
• ADVANCED – What is a weakness of vSphere FT ? (Answer: does not protect you against OS crash and any OS changes (good and bad) are replicated to the secondary VM)
• ADVANCED – How many times will vSphere HA try to restart a failed VM? (Answer: 5 times over 30 minutes)
• EXPERT – How long does the Master election process take? (Answer: 15 seconds via UDP protocol)
• EXPERT – What protocols and ports does vSphere HA use? (Answer: UDP and TCP via port 8182)
• EXPERT – What are the default slot sizes? (Answer: 32MHz CPU and 0MB Memory)
• EXPERT – What are the valid vSphere HA states? (Answer: Running, Isolation, Partitioned, Failed, FDM Agent Down)
• EXPERT – What are the valid Host Isolation Responses? (Answer: Leave Powered On, Power Off, Shutdown)
• EXPERT – What are the valid Restart Priorities? (Answer: Disabled, Low, Medium, High)
• Additional questions: What are the remote and local file locations for vSphere HA?  What information is stored here?  What purpose does it serve?  What is Datastore Heartbeating?  What is the difference between Isolation and Network Partition?  What mechanism does vFT use?  What are the requirements to enable vFT?  What conditions have to be met before vSphere HA will trigger the restart of a VM?  What are the valid Admission Control settings?