Facebook gave a presentation about their development practices at OSCON in Portland last July, it was interesting (I was in the room at the time):
<a href="https://www.youtube.com/watch?v=Ax9KR_PaiEM" rel="nofollow">https://www.youtube.com/watch?v=Ax9KR_PaiEM</a><p>...the thing that sticks in my mind was, yes it runs on localhost, where the localhost dev env has 3TB SSD and 144GB of memory :)
Lots of insight—and several great projects—on their blog: <a href="https://code.facebook.com" rel="nofollow">https://code.facebook.com</a><p>Things work a little different for Facebook than they do for sites with more reasonable traffic. I've seen a few talks on YouTube where they speak about the challenges of scalability as they gradually hot swap legacy X or Y for their own in-house component Z.<p>See React/JSX and Flux, and the Haxl library. They go into detail about some of the problems and solutions that they've made public with respect to those projects, and they speak a lot about testing too in many of the posts. Worth checking out.
I'd link to an article I wrote about website testing, but I used mod_rewrite to redirect every URL on my site to "Make a Bonfire of Your Reputations".<p>When I stop being so pissed off, you'll find my article at <a href="http://www.warplife.com/tips/webmaster/web-application-testing/" rel="nofollow">http://www.warplife.com/tips/webmaster/web-application-testi...</a><p>tl;dr: use a load generator. I wrote the article after some jackass woke me and my new bridge out of bed at three in the morning because his sun ultrasparc server fell over when brought live just in time for the christmas shopping season.