Thanks - I wrote this mostly as a braindump of some of the things I discovered in investigating this stuff - We had a period of several months where we were con

Thanks - I wrote this mostly as a braindump of some of the things I discovered in investigating this stuff - We had a period of several months where we were constantly getting timeouts. There's not really a huge amount of really detailed information out there on how the different servers work and the tradeoffs between them. RE threads on MRI, I think it comes down to what your latency requirements are and the type of work as you said. I'm happy with sidekiq on MRI because it doesn't matter hugely if the process gets bogged down for 60 seconds while a ruby-heavy job runs and the other jobs run slowly - jobs are only pulled from redis when there is a spare thread, and sidekiq jobs won't timeout like web requests do. IO-heavy work will get a boost with threads on Puma, but if you get a single Ruby-heavy request running for 20 seconds serializing something, you are going to get timeouts happen. I guess it does depend on the type of app you are running - Ours is actually quite Ruby-crunching heavy, because it has to serialize some big json responses, which is still incredibly slow in Rails. Apps which don't have occasional Ruby-intensive requests wouldn't have as much trouble with all this :)