Rehosting: "lift and shift"
The Rehost strategy within the AWS Migration 6R Framework entails the migration of applications to AWS without introducing modifications. This approach is ideally suited for expeditious migration projects :
Simple migrations by re-hosting on AWS (applications, databases,data ...)
No cloud optimisations being done, application is migrated as is
It could save as much as 30% on cost
Example: AWS Server Migration Service or AWS VM Import/Export
Replatforming:
The Replatform strategy encompasses making selective optimisations for cloud benefits without redesigning the application. And the use case aimed at enhancing performance, scalability, or cost efficiency through targeted adjustments.
Example: migrate your database to RDS
Example: migrate your application to Elastic Beanstalk (Jave with Tomcat)
Repurchase: "drop and shop"
This strategy involves discarding the existing application in favor of commercial off-the-shelf (COST) or software as a service (SaaS) solutions. The use case is applied when a suitable off-the-shelf solution is available, and customisation is not required.
Moving to a different product while moving to the cloud
Often you move to a SaaS platform
Expensive in the short term, but quick to deploy
Example: CRM to Salesforce.com, HR to Workday, CMS to Drupal
Refactoring/Re-architecting:
This approach demands a complete redesign or redevelopment to fully exploit cloud-native features and optimise for the AWS environment. In terms of use case it is ideal for modernising applications for improved scalability, performance, and cost efficiency, leveraging AWS services extensively.
Reimagining how the application is architected using Cloud Native features
Driven by the need of the business to add features, scale, performance
Example: move an application to Serverless architectures, use AWS
Retire:
This strategy focuses on identifying and decommissioning redundant or obsolete applications. The use case aims to streamline the It landscape by eliminating unnecessary components, reducing complexity.
Turn off things you don't need (maybe as result of Re-architecting)
Helps with reducing the surface areas for attacks(more security)
Save cost, maybe up to 10% to 20%
Focus your attention on resources that must be maintained
Retain:
Do nothing for now (for simplicity, cost reason, importance.....)
It's still a decision to make in a Cloud Migration
In conclusion, I have confidence that this explanation has provided you with a lucid comprehension of the fundamental concept underpinning the 6R Framework.