What to Expect and Tips
• 45-minute systems interview, focus on responding to real world problems with an unhealthy service, such as a web server or database. The interview will start off at a high level troubleshooting a likely scenario, dig deeper to find the cause and some possible solutions for it. The goal is to probe your knowledge of systems at scale and under load, so keep in mind the challenges of the Facebook environment. • Focus on things such as tooling, memory management and unix process lifecycle.
More specifically, linux troubleshooting and debugging. Understanding things like memory, io, cpu, shell, memory etc. would be pretty helpful. Knowing how to actually write a unix shell would also be a good idea. What tools might you use to debug something? On another note, this interview will likely push your boundaries of what you know (and how to implement it).
Interview is all about taking an ambiguous question of how you might build a system and letting you guide the way. Your interviewer will add in constraints when necessary and the idea is to get a simple, workable solution on the board. Things like load and monitoring are things you might consider. What you consider is just as important as to what you don’t. So ask clarifying questions and gather requirements when appropriate.