- esxtop counters

- host isolation adwanced config

- DRS and DR

- Storage and Netword best practices. 

Know your PSP, SATPs storage things. A number of questions on fixed path policies and VMW_PSP_MRU, VMW_PSP_FIXED, VMW_PSP_FIXED_AP etc. (Fiber channel SAN configuration guide, page 26) 

Know your ESXtop CPU Ready / Wait values

vSphere 4.0 Security Hardening Guide pg 29 

know HA
know ESXTOP counters and thresholds
know multipathing 
know/understand "business reasons" for BCP and DRP decisions

reading the application best practices mentioned in the roadmap (SQL, Exchange, Oracle). 


“Exam time is too short, so don’t waste it reading every small bit of every question but scan through it go to the answer & see if you really need to go and digg more details. Further, don’t waste time on any question as the time is the most valuable thing when you are doing the VCAP4-DCD

Make sure you know how to size an environment without having a tool to do that on your behalf as you don’t get these tools during the exam. Further, Make sure you know all the new features & changes in vSphere 4.1

Tip - dont just focus on the technical aspect of the design, take into account the whole design process and know about such things as design risks, requirements, assumptions etc.

For those who are studying for the DCD the design workshop book VMware uses for the course is a lifesaver for this exam. I think about half of the test is pulled directly from this book. Granted I skipped through half of the book I would recommend every page that has 'best practice' be read over and remembered well.

Besides studying the Design course material I read the blueprint multiple times and know the 'VMware HA & DRS best practices' inside out 

2. Read Duncan and Franks 'vSphere 4.1 HA and DRS Technical Deepdive' book inside and out.

Make sure that you are aware of all datacenter related aspects in a VMware related environment:
Storage
Networking
Servers
OS
Power
Disaster Recovery