I was asked this by an interviewer today and unfortunately he wouldn't share the kind of answer he was looking for so I'm hoping maybe the community can help.

Say you're an engineer at company X and you begin to notice visiting x.com is slow. Assuming you're dealing with a highly distributed architecture, what questions immediately jump out at you? What steps should you take to diagnose and identify the cause?

closed as too broad by gnat, Jörg W Mittag, James McLeod, enderland, psr Mar 16 '16 at 20:17

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  • @Binvention great answers! Could you add them as an actual answer on here so I could select it? I was hoping for more input from people but it looks like you're the only one :) – smaili Mar 16 '16 at 4:09

Look at the web debugger and console to first see if there are errors. Second view network activity to see what files are taking the longest to load. If none of those are the problem start looking for processing intensive sections. Perhaps pause the script and look at the command stack to see what functions are being run the most. Things like that. Chrome also has a web page diagnostic tool that can be helpful but that largely depends on the situation. Perhaps download source files and serve them to localhost to see if it's a networking issue. If it's a network issue which might be likely with a distributed architecture see what resources are taking the longest and pinpoint what source those resources are originating from. If working with a language like php or other languages that compile at the server before being sent out check the state of the cached files and see how much the server(s) are processing with every request.

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