The 4 R’s of cloud migration refer to strategies organizations use to decide how to migrate their applications and workloads to the cloud:
- Rehost (lift and shift): Involves migrating applications from on-premises to the cloud with minimal changes to the architecture. It’s often quicker but may not fully leverage cloud benefits.
- Refactor (rearchitect): Involves redesigning applications to take advantage of cloud-native features, like microservices or serverless computing, improving scalability and performance.
- Revise (replatform): Involves making slight modifications to applications to optimize them for cloud environments, such as switching to a different database or middleware.
- Replace: Involves adopting new software solutions that are cloud-native instead of migrating existing applications directly.
The stages of cloud migration typically involve the following steps:
- Assessment and planning: Evaluating current IT infrastructure, applications, and dependencies to determine migration readiness and strategy.
- Proof of concept (PoC) or pilot: Testing migration strategies on a smaller scale to validate feasibility and identify potential issues.
- Migration execution: Actual migration of applications, data, and workloads to the cloud platform, following the chosen strategy (e.g., rehosting, refactoring).
- Optimization and monitoring: Fine-tuning applications and infrastructure in the cloud, optimizing performance, cost, and security, and monitoring for ongoing management and improvement.
The 5 R’s in cloud migration expand on the 4 R’s and include:
- Retire: Decommissioning applications or systems that are no longer needed or suitable for migration to the cloud.
- Retain: Keeping certain applications or data on-premises due to regulatory requirements, cost considerations, or technical constraints.
- Revisit: Re-evaluating applications and infrastructure periodically to assess their suitability for cloud migration as technology and business needs evolve.
- Repurchase: Adopting new cloud-based software as a service (SaaS) solutions to replace existing applications.
- Reskill: Providing training and development opportunities for teams to acquire skills necessary for managing cloud environments effectively.
The 7 Rs in cloud migration encompass a broader range of considerations and decisions:
- Rehost (lift and shift): Moving applications to the cloud without significant modification.
- Replatform (lift, tinker, and shift): Making some adjustments to applications for better compatibility with cloud services.
- Repurchase (drop and shop): Replacing existing applications with equivalent cloud-based services.
- Refactor/rearchitect: Restructuring applications to take full advantage of cloud capabilities like scalability and resilience.
- Rebuild: Completely redesigning applications using cloud-native architectures and services.
- Retire: Phasing out applications or services that are no longer needed.
- Retain: Keeping certain applications or data on-premises for various reasons such as compliance or performance requirements.