> The purpose of the system design interview is to convince me that you could build, or lead a team to build, the thing that we are discussing at a company like the one where you are interviewing. I feel like I can easily see through interview practice or coaching, so I don't recommend spending more than an hour or so "preparing" for system design interviews. Unless you are interviewing somewhere with very inexperienced interviewers...
I don't agree with this because I bombed a couple interviews till I spent the time going through the prep. I distinctly remember an interview completely going off the rails because I was asked about a retail Web site and said "honestly I'd usually start with a simple app server - SQL database setup to start; no reason for the complexity of anything more complex till you've proven you've got the traffic and have scaling problems." That's my honest opinion, borne out by real-world experience, for most people thinking of doing something like that, but it obviously wasn't what the interviewer wanted to hear and it's not like I would have been capable of giving a fancier design; I just didn't know how you're supposed to approach the question.
Well I know that now because I watched a bunch of prep videos and then easily passed interviews despite my experience not significantly changing in the intervening time. But that's my point; if you don't prep you have to just guess which aspects of this pretend scenario you're meant to be taking seriously and which are OK to gloss over. I had other interviews go off the rails because I offered too much detail about a smaller part of the system and discussion of it dominated the entire time but even though the interview kept engaging this discussion it wasn't actually what they wanted. "Don't bother prepping because you can't; it's just measuring your real abilities" is just not right, in my opinion.
I don't agree with this because I bombed a couple interviews till I spent the time going through the prep. I distinctly remember an interview completely going off the rails because I was asked about a retail Web site and said "honestly I'd usually start with a simple app server - SQL database setup to start; no reason for the complexity of anything more complex till you've proven you've got the traffic and have scaling problems." That's my honest opinion, borne out by real-world experience, for most people thinking of doing something like that, but it obviously wasn't what the interviewer wanted to hear and it's not like I would have been capable of giving a fancier design; I just didn't know how you're supposed to approach the question.