Big migrations, no heroics
The all-nighter cutover is a failure of planning dressed up as dedication. How to migrate critical systems calmly, in daylight.
The legend of the heroic weekend migration is one the industry should retire. When a cutover requires heroics, it means the plan left no room for anything to go wrong, and something always does.
The calm alternative is incremental. Run the new system alongside the old, route a trickle of traffic to it, and compare the results. Increase the trickle only as confidence grows. Keep rollback one click away at every step.
Done this way, a migration stops being an event and becomes a process. There's no big night, no war room, no crossed fingers. Just a slider you move from 0 to 100 over days or weeks, watching the numbers the whole time.
It's less dramatic, and that's the point. The best migrations are the ones nobody outside the team even notices happened.