A large enterprise is planning to migrate hundreds of on-premises applications to AWS. The applications vary widely in complexity, from simple web servers to monolithic enterprise resource planning (ERP) systems with tightly coupled databases. The enterprise's primary goal is to minimize downtime during migration and optimize costs post-migration. They have a limited internal team with AWS expertise. Which migration strategy should the enterprise prioritize for the majority of its applications to achieve these goals efficiently?
- ARefactor (Re-architect) all applications to be cloud-native, utilizing microservices and serverless technologies from the outset.
- BRehost (Lift-and-Shift) using AWS Server Migration Service (SMS) for all applications, followed by manual re-architecture.
- CReplatform (Lift-Tinker-and-Shift) where applicable, leveraging managed services like Amazon RDS and AWS Elastic Beanstalk, combined with rehost for simpler applications.
- DRepurchase (Drop-and-Shop) by replacing all existing applications with SaaS solutions, and decommission the on-premises infrastructure.
Show answer & explanationAnswer & explanation
Correct answer: C. Replatform (Lift-Tinker-and-Shift) where applicable, leveraging managed services like Amazon RDS and AWS Elastic Beanstalk, combined with rehost for simpler applications.
Replatforming allows for some optimization and cost savings by moving to managed services without a complete re-architecture, balancing the need for modernization with minimizing initial effort. Combining it with rehosting for simpler applications provides a pragmatic approach given the varied complexity and limited internal expertise.
Why the other options are wrong
- A. Refactoring all applications upfront is a highly complex, time-consuming, and expensive strategy, not suitable for minimizing downtime or a limited team, especially for hundreds of applications.
- B. Rehosting alone might not optimize costs or leverage cloud benefits sufficiently in the long term for complex applications, and manual re-architecture afterward is resource-intensive.
- D. Repurchasing all applications with SaaS might not be feasible for highly customized enterprise applications and could lead to significant data migration challenges and vendor lock-in.
The 6 R's of Migration
A framework outlining different strategies an organization can adopt when migrating applications to the cloud, each with varying levels of effort, cost, and cloud benefits.
- Developed by AWS to categorize migration approaches.
- Helps organizations choose the most appropriate strategy for each application.
- Impacts cost, complexity, and time-to-value for cloud adoption.
Memory trick: Remember the Six Rs: Rehost, Replatform, Refactor, Repurchase, Retain, Retire.