Cloud migration moving your applications, data, and infrastructure from on-premise systems to cloud platforms is one of the most significant technology initiatives a business can undertake. Done well, it reduces costs, improves scalability, and unlocks capabilities that drive competitive advantage. Done poorly, it creates disruption, cost overruns, and security risks.
This guide provides a comprehensive framework for planning and executing a cloud migration that delivers on its promise.
The 6 Rs of Cloud Migration
The most widely used framework for cloud migration strategy is the "6 Rs" six different approaches to migrating each application or workload:
1. Rehost ("Lift and Shift")
Move applications to the cloud without modification. This is the fastest and lowest-risk migration approach, but it doesn't take full advantage of cloud capabilities. Best for: applications that need to move quickly, legacy systems that can't be easily modified, or as a first step before optimization.
2. Replatform ("Lift, Tinker, and Shift")
Make minor optimizations to take advantage of cloud capabilities without changing core architecture. For example, moving a database to a managed cloud database service. Best for: applications where modest cloud optimization is achievable without full re-architecture.
3. Repurchase ("Drop and Shop")
Replace an existing application with a cloud-native SaaS alternative. For example, replacing an on-premise CRM with Salesforce. Best for: commodity applications where a SaaS alternative exists and switching costs are manageable.
4. Refactor / Re-architect
Redesign the application to be cloud-native typically adopting microservices, containers, and serverless architectures. This delivers the greatest long-term benefits but requires the most effort. Best for: applications that are strategic, high-value, and need to scale significantly.
5. Retire
Decommission applications that are no longer needed. Migration projects often reveal that 1020% of applications can simply be retired, reducing complexity and cost.
6. Retain
Keep certain applications on-premise, at least temporarily. Some applications may have regulatory requirements, technical dependencies, or business reasons that make cloud migration impractical in the near term.
Phase 1: Discovery and Assessment
Before migrating anything, you need a comprehensive inventory of your current environment. This includes: all applications and their dependencies, server specifications and utilization patterns, data volumes and sensitivity classifications, network topology and bandwidth requirements, and compliance and regulatory requirements.
