My general line of questioning is as follows:
1) Explain to me a system you built/architected. How it worked, what it did, etc. I'm looking for a deep understanding around the requirements of the business, and how that played into technical choices.
2) Talk me through some bugs you encountered or mistakes you made, and how you course corrected. I try to make a candidate comfortable prior to asking this and usually tell a quick and horrifying war story from my own career. Here I want to understand how a candidate processes information and adapts the plan accordingly. Like mike tyson said, everyone's got a plan until they get hit.
3) If you had to build the system again today, what would you do differently? I'm looking for an awareness of how technology has evolved since they designed the system in question, as well as what didn't work well over time from an operational perspective (e.g. we didn't burn off time series data over time so table index rebuilds started to take forever, etc). I want to make sure the candidate supported the system they designed over time, and felt the pain/benefit of their decisions. I usually specifically ask the candidate at the beginning to pick a system they built and supported for an extended period of time.
I also ask about areas of technical expertise, and areas where the candidate feels less strong technically. For the former, I make sure they have the kind of expertise they claim, and for the latter, I want to see how they communicate with team members that are expert in those areas (and how they gain familiarity with new technologies).
1) Explain to me a system you built/architected. How it worked, what it did, etc. I'm looking for a deep understanding around the requirements of the business, and how that played into technical choices.
2) Talk me through some bugs you encountered or mistakes you made, and how you course corrected. I try to make a candidate comfortable prior to asking this and usually tell a quick and horrifying war story from my own career. Here I want to understand how a candidate processes information and adapts the plan accordingly. Like mike tyson said, everyone's got a plan until they get hit.
3) If you had to build the system again today, what would you do differently? I'm looking for an awareness of how technology has evolved since they designed the system in question, as well as what didn't work well over time from an operational perspective (e.g. we didn't burn off time series data over time so table index rebuilds started to take forever, etc). I want to make sure the candidate supported the system they designed over time, and felt the pain/benefit of their decisions. I usually specifically ask the candidate at the beginning to pick a system they built and supported for an extended period of time.
I also ask about areas of technical expertise, and areas where the candidate feels less strong technically. For the former, I make sure they have the kind of expertise they claim, and for the latter, I want to see how they communicate with team members that are expert in those areas (and how they gain familiarity with new technologies).