2 min lesson
Incremental cutover beats big-bang
Answer this. "You're sequencing a serving-stack migration at the 1M+ DAU scale this exercise assumes, and an engineer proposes a single weekend big-bang cutover to 'rip the bandaid off.' How do you respond?"
Step 1 of 3
Incremental cutover beats big-bangblast radius is the metric
When you migrate a serving stack at production scale, the question that matters is how many users felt it if it didn't work. Big-bang cutover bets the whole user base on a single switch. Incremental cutover bets 1%, watches, then 5%, then 25%.
Interactive diagram. Step through it with the Next and Previous controls below, or Tab to a region to read its detail.
diagram: flow
Each gate is a guardrail-metric check you pass on evidence, with rollback kept hot the whole way.