Moving to the cloud is one of the most common technology initiatives of the decade — and one of the most commonly botched. The promise is real: flexibility, scale, and modern capability. But the graveyard of cloud migrations is full of projects that lifted old problems into a new environment, blew through budgets, and left teams wondering why the cloud cost more and worked worse than what they left behind. The difference between those failures and the successes is almost never the technology. It's the cloud migration strategy — the plan that decides what moves, how, in what order, and why.
This guide covers what cloud migration actually involves, the well-established options for moving each application, the phases that structure a sound migration, the pitfalls that sink projects, and how to move without breaking things.
What Cloud Migration Actually Is
Cloud migration is the process of moving applications, workloads, and infrastructure from on-premises data centers (or another cloud) into a cloud environment. It's worth distinguishing from a related term: this is about moving workloads and applications, whereas moving data between systems and databases is its own discipline, covered in this complete guide to data migration. The two overlap — most application migrations involve moving data — but they're scoped and planned differently, and confusing them is a common early mistake.
The strategic point is that cloud migration is not a single action but a portfolio decision. Different applications warrant different treatment, and the art is matching each one to the right approach rather than applying one method to everything — which is exactly what the established migration options exist to structure.
The 6 Rs: How Each Application Moves
The industry organizes migration approaches into a well-known set of options, often called the 6 Rs. Knowing them turns "move to the cloud" into a series of deliberate, defensible choices.
Rehost ("lift and shift"). Move the application as-is to cloud infrastructure. Fast and low-risk, ideal when speed matters or as a first step — but it carries existing inefficiencies along and doesn't capture the cloud's full value on its own.
Replatform. Move with modest optimizations — swapping in a managed database, for instance — capturing some cloud benefit without a full rebuild. A pragmatic middle path.
Refactor. Re-architect the application to be cloud-native, unlocking the most scalability and efficiency at the highest cost and effort. Reserved for the applications where the payoff justifies it.
Repurchase. Replace the application with a cloud-based product — moving off a self-hosted system onto a SaaS equivalent, the shift explored in this guide to cloud-based ERP systems.
Retain. Deliberately keep certain workloads where they are — some systems shouldn't move yet, or ever, for technical, compliance, or economic reasons. A conscious "not now" is a valid strategic choice.
Retire. Decommission what's no longer needed. Migration assessments routinely uncover applications nobody uses, and turning them off is the cheapest win available.
The strongest strategies mix these across the portfolio — rehosting the simple, refactoring the strategic, repurchasing the commodity, retiring the dead weight. Applying a single approach to everything is the first sign of a migration in trouble, and reflects the same match-the-approach-to-the-need discipline behind treating cloud services as a deliberate strategy.
The Phases of a Sound Migration
Structured migrations follow a clear sequence, and skipping the early phases is where most failures originate. Established methodologies — like Google Cloud's adoption framework and its equivalents from other providers — all share the same backbone: assess, plan, migrate, optimize.
Assess. Inventory the applications, dependencies, and data. Understand what talks to what, what the compliance requirements are, and what each workload actually needs. This phase determines everything downstream, and rushing it guarantees surprises mid-migration.
Plan. Decide the approach for each application (the 6 Rs), sequence the migration into waves, define success criteria, and design the target architecture, security model, and cost structure before moving anything.
Migrate. Execute in waves, starting with lower-risk applications to build capability and confidence, validating each wave before the next. Big-bang migrations of everything at once are how organizations turn a project into a crisis.
Optimize. Migration isn't done at cutover. Right-sizing, cost management, and capturing cloud-native benefits happen after workloads land — the discipline covered in this guide to cloud cost optimization, and the phase that separates migrations that pay off from those that just relocate the bill.
The Pitfalls That Sink Migrations
The failure modes are consistent and avoidable.
Lift-and-shift everything. Rehosting every workload unchanged and expecting cloud benefits — then discovering the cloud costs more because you moved inefficiency into a metered environment. Migration is the natural moment to right-size, not to relocate waste.
Skipping assessment. Moving without understanding dependencies, so applications break when the systems they quietly relied on aren't there. Nearly every migration horror story traces back to a shallow assessment phase.
Big-bang cutover. Migrating everything simultaneously instead of in waves, multiplying risk and leaving no room to learn. Phasing is protection.
Ignoring security redesign. Cloud security is a shared responsibility with a different model than on-premises, so lifting old security assumptions into the cloud leaves gaps — exactly the ownership questions laid out in this guide to cloud security services.
No cost governance. Arriving in the cloud with no plan for managing spend, then watching bills climb without accountability. Cost discipline belongs in the plan, not the post-mortem.
Neglecting the operating model. The cloud changes how teams work — automated infrastructure, continuous delivery, new skills. Migrating the workloads without evolving the practices, like the pipeline disciplines covered in this guide to AWS DevOps consulting, leaves the organization running cloud infrastructure with pre-cloud habits.
Getting Started
Assess honestly before committing to a timeline. Understand your applications, dependencies, and requirements first. A thorough assessment feels slow and prevents the expensive surprises that feel much slower.
Start with a lower-risk wave. Migrate something meaningful but not mission-critical to build capability, prove the approach, and learn — before touching the systems the business can't live without.
Design security and cost in from the start. Both are far cheaper to build into the target architecture than to retrofit after workloads land.
Right-size as you migrate. Treat migration as the opportunity to correct inefficiency, not preserve it — the single biggest lever on whether the cloud saves money.
Plan for the operating model, not just the move. Evolve the team's practices alongside the infrastructure, so the cloud's capabilities are actually used. Whether the target is AWS or Azure, an experienced cloud computing partner compresses the learning curve and keeps a migration from becoming a cautionary tale.
FAQs
What is a cloud migration strategy?
It's the plan for moving applications, workloads, and infrastructure to the cloud — deciding what moves, how each application is handled, in what order, and why. A good strategy treats migration as a portfolio decision, matching each workload to the right approach rather than applying one method to everything.
What are the 6 Rs of cloud migration?
They're the standard options for handling each application: rehost (lift and shift as-is), replatform (move with modest optimizations), refactor (re-architect as cloud-native), repurchase (replace with a SaaS product), retain (deliberately keep in place), and retire (decommission what's unused). Strong strategies mix these across the portfolio.
What's the difference between cloud migration and data migration?
Cloud migration moves applications, workloads, and infrastructure to the cloud, while data migration moves data between systems or databases. They overlap — most application migrations involve moving data — but they're planned and scoped differently, so it helps to treat them as related but distinct disciplines.
Why do cloud migrations fail?
Most failures trace to strategy, not technology: lifting everything unchanged and expecting cloud benefits, skipping the assessment of dependencies, attempting big-bang cutovers, ignoring the different cloud security model, and arriving with no cost governance. Each is avoidable with a proper assess-plan-migrate-optimize approach.
Should we lift and shift or re-architect for the cloud?
It depends on the application. Lift and shift (rehosting) is fast and low-risk, good for speed or as a first step, but captures limited cloud value. Re-architecting (refactoring) unlocks the most benefit at the highest cost, so it's reserved for strategic applications. Most portfolios use a mix based on each workload's value.
Final Thoughts
A cloud migration strategy is what turns "move to the cloud" from a gamble into a plan: assess before you commit, match each application to the right one of the 6 Rs, migrate in waves, and optimize once workloads land. The failures almost always come from rushing the assessment, lifting waste unchanged, or attempting everything at once — and all of those are choices, not fates. Move deliberately, and the cloud delivers what it promised.
Planning a move to the cloud and want it done right? Book a free consultation with ATH Infosystems' cloud experts today.