Cloud Migration Strategies

Moving an existing application to the cloud can follow several different strategies, ranging from a straightforward lift-and-shift to a full architectural redesign for cloud-native benefits.

Common Migration Strategies

Often summarised as the "6 Rs" of cloud migration, these strategies represent increasing levels of effort and increasing potential benefit from cloud-native capabilities.

• Rehost ("lift and shift") — move an application as-is onto cloud infrastructure with minimal changes.
• Replatform — make small optimisations during the move, like switching to a managed database, without a full redesign.
• Refactor/re-architect — redesign the application to fully take advantage of cloud-native features (like serverless or auto-scaling).
• Retire — decommission applications no longer needed, rather than migrating them at all.
• Retain — keep certain systems on-premises, at least for now, if migration isn't yet practical or beneficial.

Choosing a Strategy

Rehosting is fastest and lowest-risk, useful as a first step or for applications not worth redesigning. Refactoring takes significantly more time and effort, but can unlock meaningful gains in scalability, resilience, and cost efficiency for applications that will run in the cloud long-term.

Common Mistakes

• Rehosting an application "as-is" and expecting to automatically gain cloud-native benefits like elasticity, which actually require architectural changes.
• Attempting a full refactor for every application regardless of its long-term importance, spending disproportionate effort on low-value systems.
• Underestimating the effort and risk involved in a large-scale migration, leading to unrealistic timelines.
• Forgetting to evaluate whether an application should simply be retired rather than migrated at all.