Cloud Migration Patterns
Moving to
the cloud isn't a "one size fits all" process. The strategy you
choose depends on your business goals, budget, and the technical debt of your
current applications.
The industry
standard for these patterns is often referred to as the "6 Rs of
Migration," originally defined by AWS.
1. Rehost
("Lift and Shift")
This is the
quickest way to migrate. You move your applications from on-premise servers to
the cloud without making any changes to the code or architecture.
- Best for: Rapid migration, legacy
systems that are hard to modify, or when a data center is closing quickly.
- Pros: Fast, low risk, minimal
training required.
- Cons: Doesn't take advantage of
cloud-native features like auto-scaling; can be more expensive in the long
run.
2.
Replatform ("Lift, Tinker, and Shift")
You make a
few optimizations to the application to take advantage of cloud capabilities,
but the core architecture remains the same.
- Example: Moving a self-managed SQL
database to a managed service like AWS RDS or Google Cloud SQL.
- Best for: Reducing the overhead of
managing infrastructure without rewriting code.
3.
Refactor / Re-architect
This
involves reimagining how the application is architected and developed using
cloud-native features. This often means moving from a monolith to microservices.
- Best for: Applications that need
high scalability, performance, or agility.
- Pros: Most cost-effective and
powerful in the long term.
- Cons: Most expensive and
time-consuming upfront; requires high-level dev expertise.
4.
Repurchase ("Drop and Shop")
You stop
using your existing legacy system and move to a SaaS (Software as a
Service) platform.
- Example: Moving from an on-premise
CRM to Salesforce, or from self-hosted email to Microsoft 365.
- Best for: Standard business
functions (HR, CRM, Email) where custom code provides no competitive
advantage.
5. Retain
(Do Nothing)
Sometimes,
it doesn't make sense to move an application yet. You keep it in its current
environment.
- Why: High complexity, strict
compliance/data residency requirements, or the app is scheduled to be
retired soon anyway.