Instagram is a living example for when you have big scaling problems you just scale. You are probably right with your arguments... the question is: Is it worth to choose a good scaling architecture when it slows your initial development down? Instagram is python, many Youtube parts are python, FB is even worse and is PHP at many parts.
So what? Sure they would scale better when using Erlang, Java or Go... but sometimes it is wiser to finish building something than making the best ultrascalable system. If you are really successful you will find ways to scale.
I've heard this so many times but I always wonder how the unicorn effect skew this. Do a majority of companies with such scaling issues fail? I've seen products go down in flames firsthand because performance was so bad. Never at a start-up but I assume it happens there too.
Facebook is a good example because of all the money they've thrown at a problem they shouldn't have. First was a custom PHP interpretor then a compiler and now hack. If they didn't have nearly unlimited money to throw at it would things have ended differently?
Language choice is one of the easiest choices to make. Pick a fast one out of the box if you plan to get big. It's not like the faster languages take orders of magnitude longer to write code in, the effect is minimal at best.
because it doesn't. What they're doing is borderline crazy. Similar to turning off the GC in the JVM... once you reach that point why not just use a more suitable language?
Java/Golang/Rust/C++/C# are all about 100X faster than Python. Wouldn't it be more reasonable to use one of those than mess with the runtome to squeeze out 20% more performance?
Forking threads for web pages is so old school...And Python is a terrible choice for something at their scale.
Just redo the hosting bit in Java or golang and call it a day. If their UI code is sufficiently isolated from the back end it's not a huge deal.
Instagram is a pretty small application feature-wise, a few devs could probably do it in a couple months