From a monolithic Ruby on Rails app to the JVM, how Soundcloud has transitioned to a hybrid approach with Ruby apps intermingling with Scala and Clojure apps. I think some of their idea of what is idiomatic Rails and how to operate Ruby are not exactly on center. But, their approach to the problem of a large Rails app is right on: break it up into “micro-services” that, if you don’t like the code, you can rewrite quickly if necessary.
Lest you fear this is yet another “Rails doesn’t scale!” deck, they do make a key observation. “Rails, PHP, etc. are a very good choice to start something”. Once you get past “starting” and “growing” to “successful and challenging”, you’ll face the same level of challenge no matter what you choose: Ruby or Java, MySQL or Riak. All the technologies we have today are challenged when they grow large.
So don’t let applications and services get large. Easy to say; hard, but worthwhile, to practice.