The best migration I ever ran took six months and made almost no headlines. That was the whole point.
Boring on purpose
We never had a cutover weekend. Instead we ran old and new in parallel, dual-writing, then dual-reading with the new path shadowed and compared against the old. Every week we moved a little more traffic and deleted a little more old code.
What made it boring:
- Reversible at every step — any week we could stop and still be correct.
- Differences surfaced as metrics, not surprises.
- No single moment where everything had to work at once.
Exciting migrations make for good war stories. Boring ones make for good sleep.