Cloud migration failures are almost never caused by the wrong technology choice. They're caused by insufficient planning, incomplete dependency mapping, and the misguided belief that downtime windows are acceptable.
Why migrations actually fail
Rarely is the destination platform the problem. Migrations fail because the dependency map was incomplete, the cutover window assumed a best-case scenario, and there was no tested path backward if something broke at 2 a.m. on launch night.
Dependency mapping before anything else
Before scheduling a single migration window, catalogue every system that reads from or writes to the system being moved — including the ones nobody remembers, like the reporting job a finance analyst built four years ago. Automated discovery tools catch network-level dependencies; they miss batch jobs, scheduled exports, and anything triggered by a cron entry on a server nobody has logged into recently. Interview the teams, not just the infrastructure.
The parallel-run window
Zero-downtime migrations don't happen by cutting over faster — they happen by running both environments in parallel long enough to catch discrepancies under real production load, not synthetic test traffic. Budget for a parallel-run period of at least two full business cycles, including month-end processing if relevant, before decommissioning the source system.
Rollback is not optional
Every migration plan needs a tested, documented rollback procedure that has actually been executed once in a staging environment — not just written down. If your rollback plan has never been tested, it isn't a plan, it's a hope. The migrations that become incidents are, almost without exception, the ones where the team discovered during a live failure that the rollback script didn't actually work.