Why Cloud Migration Decisions Are More Complex Than They Appear
The pitch is simple: move your infrastructure and applications to the cloud, reduce IT overhead, improve scalability, and cut costs. In practice, cloud migrations involve complex trade-offs, require significant upfront planning, and can go badly wrong when organisations rush in without a clear strategy.
This guide is designed for business and IT leaders who are either planning a migration or evaluating whether now is the right time.
Understanding the "6 Rs" of Cloud Migration
Not every application should be migrated the same way. The "6 Rs" framework helps you categorise each workload:
- Rehost (Lift & Shift): Move the application as-is to cloud infrastructure. Fast and low-risk, but doesn't take advantage of cloud-native features.
- Replatform: Make minor optimisations during migration (e.g., move to a managed database service) without changing core architecture.
- Refactor/Re-architect: Rebuild the application to be cloud-native. Highest effort, highest long-term benefit.
- Repurchase: Replace the existing application with a cloud-native SaaS alternative.
- Retain: Keep the application on-premise for now (legacy systems with complex dependencies, compliance constraints).
- Retire: Decommission applications that are no longer needed.
Most organisations end up with a mix of these strategies across their application portfolio.
Building Your Migration Business Case
Before committing to a cloud migration, build a clear business case that addresses:
- Total cost of ownership comparison: Current on-premise costs vs. projected cloud costs (including hidden costs like egress fees, storage, and support)
- Business agility gains: Faster deployment, easier scaling, improved remote access
- Risk reduction: Improved disaster recovery, vendor-managed security patches
- Opportunity costs: What could your IT team do if they weren't managing physical infrastructure?
Key Decisions Before You Start
Which Cloud Provider?
The major providers — AWS, Microsoft Azure, and Google Cloud — each have strengths. Azure tends to suit organisations already invested in the Microsoft ecosystem. AWS offers the broadest service catalogue. Google Cloud has strengths in data and AI workloads. For most businesses, the decision comes down to existing tooling, partner support, and pricing.
Single Cloud or Multi-Cloud?
Multi-cloud can reduce vendor dependency and allow best-of-breed selection, but it adds complexity in management, security, and cost governance. Start with a primary cloud provider unless you have a specific business reason for multi-cloud from day one.
Migration Risks to Plan For
| Risk | Mitigation |
|---|---|
| Data loss during migration | Run parallel environments; validate data integrity before cutover |
| Application performance degradation | Load test in the cloud environment before going live |
| Cost overruns | Set up cloud cost monitoring and budget alerts from day one |
| Security misconfiguration | Apply cloud security benchmarks (e.g., CIS Controls); conduct pre-launch security reviews |
| Staff skill gaps | Invest in cloud training early; consider managed service partners |
A Phased Migration Approach
- Assess: Inventory all applications and infrastructure; apply the 6 Rs framework
- Plan: Define migration waves, starting with low-risk, high-value workloads
- Pilot: Migrate one or two non-critical applications to validate approach and build team experience
- Migrate: Execute migration waves with clear rollback plans for each
- Optimise: After migration, right-size resources, implement governance, and continuously improve
Final Thoughts
Cloud migration done well is genuinely transformative — improving resilience, reducing maintenance burden, and giving businesses more flexibility to scale. Done poorly, it creates new complexity and unexpected costs. The difference almost always comes down to the quality of planning before the first workload moves.