VCDX Skill Technology Deepdive

Originally posted in September 2015 on

I was going to create a single post with technology deepdives and BC/DR but it got to long, so another post will include the BC/DR content.

The Technology Deepdives included a skill transfer list of specific technologies (mostly VMware) to better understand and be better qualified to explain what impact the technology could have had on the design.

For myself I created two extra skill updates just including specific core vSphere technologies:

  • vSphere HA
  • vSphere DRS (including resource control)

The only resource for these were, and you might have guessed it, the vSphere HA and DRS bible, VMware vSphere 5.1 Clustering Deepdive (Volume 1) by Duncan Epping and Frank Denneman . If you have not read this book I recommend you buy a copy and read it through. It has great information on a lot of core VMware technologies.

Here are a couple of question and answers I created for these:

What is the difference between a Master agent and a Slave agent? Master agent is in charge of monitoring the health of VM and restarts any that fail.
Slave agents forwards information to the master agent and restarts VM by the command from the master.

What role does vCenter have in protecting VMs in HA? When VM state changes, vCenter directs the master to enable or disable HP protection for that VM. But is only guaranteed when the changes have been written in the protectedlist file.
Master will then inform vCenter so changes are visible in vCenter and for monitoring tools.

What impact does DRS have on vCenter sizing? Each cluster has a specific DRS thread running on the vCEnter to do the calculations every 5 minutes.

How many concurrent vMotions supported?

  • On 1Gb:4
  • On 10Gb: 8
  • On 40Gb: 8

How is the dynamic entitlement target for a VM calculated? The DET consists of demand and usage metrics. CPU active (% Run+ % ready) and Memory active (Active+overhead+25%idle consumed)

And here is a slide from the VCDX deep dives section:


A technology deepdive can include any technology used in the design and does not have to include VMware technologies specifically (even though there is a good chance a question would be about that not an advanced config for, let say, a Trend Micro configuration)

I did not spend extensive time on learning everything but just so much that I had an expert level skill level on the topic and how each technology could impact my design. I think that should be something that needs to come across that you can show you know the technology on an expert level and really thought about how the technology impacts designs or fulfilled requirements.