migration-strategy

name	migration-strategy
description	Plan large-scale migrations from old systems to new architectures. Use when modernizing legacy systems or upgrading infrastructure.

Migration Strategy

Plan phased migrations that minimize risk and disruption while delivering value incrementally.

Instructions

1. Assess Current State: What's working? What's broken?
2. Define Target State: New architecture vision
3. Identify Seams: Where can you break the system into phases?
4. Plan Phases: Each phase delivers value; takes weeks to months
5. Risk Mitigation: Parallel running, feature flags, rollback plans
6. Success Metrics: How do we measure success of each phase?

Anti-Patterns

• Big Bang Rewrite: Replace everything at once. Result: chaos and failure. Guard: Incremental, staged migration.
• No Parallel Running: Migrate directly without validation. Guard: Run old and new in parallel, validate.

Further Reading

• Strangler Fig Pattern — incremental replacement
• Monolith to Microservices by Sam Newman