Database Migration -

The application is updated to write data to both the old and new databases simultaneously. This keeps the new system "warm" and up-to-date.

You must map every dependency—every table, view, and stored procedure.

Early attempts to move often look like a "Big Bang" approach. You turn off the application, copy the database, and turn it on in the new location. database migration

A dedicated "tiger team" tests every byte to ensure data integrity. Chapter 3: The Darkest Hour (When Things Go Wrong)

Here is the story of how that migration happens, from disaster to triumph. Chapter 1: The Disastrous "Big Bang" (What Not to Do) The application is updated to write data to

Smart companies choose a phased migration. They use to replicate data incrementally from the old house to the new one while people are still living in the old one.

For a high-traffic app, "turning it off" for 4 hours costs millions in revenue and causes massive customer anger. Early attempts to move often look like a "Big Bang" approach

Despite the best planning, migrations are "10x more difficult than people think".