Migration Strategies (The 6 Rs)
The six standard approaches to moving a workload to AWS: Rehost, Replatform, Repurchase, Refactor, Retire, and Retain, each trading off speed, cost, and long-term fit differently.
Definition
The 6 Rs is the standard framework for categorising migration approaches: Rehost (lift and shift), Replatform (lift, tinker, and shift), Repurchase (move to a SaaS alternative), Refactor (redesign for cloud-native architecture), Retire (decommission entirely), and Retain (leave in place for now). Most real migrations use several of these across a single application portfolio rather than picking one strategy for everything; the right choice depends on each workload's business criticality, technical debt, and how much change the organisation can absorb at once.
In Practice
A portfolio assessment might rehost a legacy internal tool with little future investment, replatform a core application's database onto RDS, and retire three systems nobody realised were still running.