“Lift and shift” is only one of several ways to move an application to the cloud, and it is often not the best one. Treating the whole estate the same way is one of the most common reasons migrations disappoint.
Seven options, not one
AWS describes seven common migration strategies, often called the 7 Rs:
- Retire: switch off what nobody needs.
- Retain: leave it where it is, for now.
- Rehost: move it as it is (lift and shift).
- Relocate: move it at the platform level without changing the application.
- Repurchase: replace it with a different product, often software as a service.
- Replatform: make small changes to benefit from managed services, such as moving to a managed database.
- Refactor: redesign it to take advantage of cloud-native capabilities.
How to choose
Look at each application against a few questions. What does the business need from it in the next few years? How expensive and risky is it to run today? What does it depend on? How much would a change cost, and what would it save or enable?
A stable application near the end of its life is a candidate for rehosting or retirement. An application that struggles to scale or change may justify refactoring. A commodity system may be better replaced altogether. Many estates end up using four or five of the strategies at once.
Plan for after the move
Migration succeeds when the destination is ready: a secure landing zone, monitoring, backup and clear ownership of cost and operations. Moving servers unchanged and leaving the operating model untouched carries old problems into a new home, and adds cloud bills on top.
How we approach it
We assess the portfolio technically, financially and for security, choose a strategy for each workload, migrate in waves and stay to optimise afterwards. See our Migration & Modernisation work.