Cloud migration is one of the most transformative — and most risky — initiatives an enterprise can undertake. This guide covers the methodology we have refined across 200+ migrations to deliver zero data loss, zero unplanned downtime, and consistently on-time delivery.
Why Most Cloud Migrations Fail
According to Gartner, 70% of cloud migration projects run over budget, over time, or fail to meet their stated objectives. After executing over 200 enterprise migrations, we believe the root causes come down to three things: inadequate discovery, unrealistic timelines, and the absence of rollback planning.
Most organisations underestimate the complexity of their existing infrastructure. Applications that appear simple on paper have hidden dependencies: undocumented database schemas, hard-coded IP addresses, session-handling quirks that only manifest under production load.
The Four-Phase Migration Methodology
Phase 1: Discovery and Dependency Mapping (Weeks 1–4)
Discovery is the most underinvested phase in most migration projects. We dedicate a minimum of four weeks to producing a complete inventory of every application, every database, every integration point, and every non-obvious dependency.
- Deploy network traffic analysis tools to automatically discover application-to-application communication
- Interview application owners for institutional knowledge not captured in documentation
- Map database relationships, stored procedures and triggers
- Identify all scheduled jobs, batch processes and time-sensitive workflows
- Assess data volumes for accurate migration time estimates
Choosing the Right Migration Pattern
The 'lift-and-shift vs re-architect' debate is often presented as binary, but in practice most enterprise migrations involve multiple patterns applied to different workloads. We classify workloads into five categories and apply the appropriate pattern to each.
Building the Business Case
Cloud migration is expensive in the short term and rewarding in the long term. Building a credible business case requires honest accounting of migration costs, infrastructure cost changes, operational cost changes, and business value from new capabilities.
Post-Migration Optimisation
Migration is not the end — it is the beginning. The cloud provides tools for continuous optimisation that simply do not exist on-premises: auto-scaling, spot instances, intelligent storage tiering, and serverless compute. Extracting maximum value from the cloud requires ongoing engineering attention.