This talk is about more than Unicorns. This is a scary talk about scary Ruby internals. Disregard the Unicorns, actually. There's a lot going on under the hood in MRI, YARV and Rubinius. The C and C++ layer that interacts with the OS is a tangly mess full of tricky bugs and arcane issues; the kind of issues that don't raise exceptions, but kill whole processes and make them bleed rainbows. Every time one of these "glitter bullets" kills a Ruby process, I shed a small tear: This is a talk about how we discover, tackle and fix these kind of issues at GitHub, to ensure our servers are always up and serving requests.