This is a great write up - making these public with all the gory technical details helps us all be better at our jobs.

I’m curious whether shutting down the east coast apps entirely and running off of the west coast was considered? Not enough capacity or some other problem?

edit: I guess the third technical initiative strongly implies that it was just a capacity issue: "This project has the goal of supporting N+1 redundancy at the facility level. The goal of that work is to tolerate the full failure of a single data center failure without user impact."