i've checked how many pageviews we've got the very next day, it's >100K as well. that's without caching. i have not observed any problems that day. the real deal here is handling such jump in a very few seconds.
and yes, increasing ulimits should be standard. one does simply forgets every single optimization when you just have to deliver a working app.
Sudden increases are hard for any app. I just find it strange that, when you talk about Redis with such familiarity, you'd choose a new technology with 4 days to launch. An F1 car might be fast, but if I had to race one I'd end up in a wall.
In saying that, I'm quite envious of your job, that sounds pretty cool (until things go wrong).
it is definitely both cool and exciting but depressing and stressing as well. i think every developer should have this experience at some point of their carrier.
and yes, increasing ulimits should be standard. one does simply forgets every single optimization when you just have to deliver a working app.