Gartner’s 5R’s – Rehost, Refactor, Revise, Rebuild, and Replace – is a great starting point for deciding on a cloud migration strategy. Here is a quick synopsis:
Also called ‘lift and shift,’ rehosting is simply takes the existing data applications and redeploys them on cloud servers. This works great for beginners, who are not yet accustomed to provisioning workloads in the cloud or for systems where code modifications are extremely difficult.
Also called ‘lift, tinker, and shift,’ refactoring involves making some optimizations and changes for the cloud and employing a platform-as-a-service (PaaS) model. Applications keep their core architecture unchanged but use cloud-based frameworks and tools.
This approach involves making architectural and code changes before migrating to the cloud. The objective is to optimize the application to take complete advantage of cloud services, such as introducing major changes to the code.
Similar to Revise in its big-bang approach, Rebuild discards the existing code base in favor of a new one. For example, moving from Java to .NET. This is a time-consuming process and is only used when there is consensus that the existing solution does not suit the changing business needs.
This strategy involves migrating to a third-party, vendor-based application from an existing native application. The existing application data needs to be migrated to the new system, however, everything else will be new.