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AWS Cloud Migration Checklist: Move to the Cloud with Zero Downtime

By Vruta Baldha·May 12, 2026·7 min read

Migrations go wrong when they are a big-bang leap of faith. Done in stages, with data kept in sync and a rollback ready, a move to AWS can happen with zero data loss and only minutes of downtime.

1. Assess before you move

Inventory every server, database, cron job and dependency. Decide per workload: re-host (lift and shift), re-platform (e.g. managed RDS), or leave it. A clear map now prevents surprises later.

2. Replicate to AWS

Stand up the target on AWS, EC2 or containers for compute, RDS for databases, S3 for object storage, all defined in Terraform so it is reproducible. Nothing is cut over yet; you are building the landing zone.

3. Keep data in sync

Use database replication (or AWS DMS) to stream changes from the old system to the new one, so the two stay in step right up to cut-over. This is what makes near-zero downtime possible.

4. Test for parity

Before touching production traffic, verify on the new stack:

• App behaves identically, key user journeys pass.
• Performance is equal or better.
• Backups, monitoring and alerts are live.

5. Cut over in a planned window

Do a final data sync, switch DNS to AWS, and watch the dashboards. Because the old system is still intact and in sync, rollback is just pointing DNS back, no drama.