Ch 9: System Design and Scalability

Question 1

System Design and Scalability Questions:
General Notes

Answer 1

• May seem intimidating, but can be some of the easiest questions
• Usually not many “tricks” or “gotchas”
• Designed to see how you would perform in a real world scenario
• These questions are largely about the PROCESS rather than the ultimate design
• Ask Questions
• Engage the interviewer
• Discuss trade-offs of design decisions

Question 2

Handling System Design Questions
(8 Points)

Answer 2

• Communicate
• Acknowledge interviewer concerns
• Drive
• Use the whiteboard
• Go broad first
• Estimate when necessary
• Be careful about assumptions
• State your assumptions explicitly

Question 3

System Design Questions:
Communicate

Answer 3

• A key goal of system design questions is to evaluate your ability to communicate
• Stay engaged with the interviewer
• Ask questions
• Be open about the issues of your system

Question 4

System Design Questions:
Go broad first

Answer 4

• Don’t dive straight into the algorithm part
• Don’t get excessively focused on one part

Question 5

System Design Questions:
Use the Whiteboard

Answer 5

• Helps your interviewer follow your proposed design
• Get up to the whiteboard in the very beginning
• Draw a picture of what you’re proposing

Question 6

System Design Questions:
Acknowledge Interviewer Concerns

Answer 6

• Your interviewer will likely jump in with concerns
• Don’t brush them off; validate them.
• Acknowledge the issues they point out and make changes accordingly

Question 7

System Design Questions:
Be careful about Assumptions

Answer 7

• An incorrect assumption can dramatically change the problem
• Ex: How fresh data must be is an important consideration

Question 8

System Design Questions:
State your assumptions Explicitly

Answer 8

• When you DO make assumptions, STATE them
• This allows interviewer to correct you if needed
• Shows that you are AWARE of your assumptions

Question 9

System Design Questions:
Estimate When Necessary

Answer 9

• In many cases, you might not have the data you need
• May need to estimate storage space
• Use data you DO know to help estimate what you don’t

Question 10

System Design Questions:
Drive

Answer 10

• As a candidate, you should stay in the driver’s seat
• Obviously, still TALK to your interviewer
• You should be driving the discussion.

Question 11

System Design Step
Step by Step