Glossary
Also: Cutover migration
Switching a system on a fixed date, usually over a weekend, with no intermediate state and only one attempt.
The appeal is simplicity: no parallel operation, no duplicated data, one clear date. That is exactly why it gets chosen when gradual replacement looks too expensive.
The price is the risk profile. Everything has to work at once, and the way back consists of restoring a backup while the business is down.
How you notice it
Frequently asked
For small systems with a clean data boundary, when parallel operation would cost more than the risk. The precondition is a fully rehearsed rollback with a measured duration. Without that rehearsal it is not a migration, it is a bet.