Cloud migration is the process of moving your applications, data, and workloads from on-premise servers or one cloud to another, in order to gain scalability, flexibility, and often lower cost. Done well, it modernises how you run software; done badly, it moves your problems to a more expensive place. The difference is planning and a clear reason for moving. This guide is the complete, step-by-step resource for migrating to the cloud without surprises.
Cloud migration matters because the cloud has become the default place to run modern software, and the organisations that migrate well gain speed and scale that on-premise infrastructure cannot match. But migration is also where a lot of budget and goodwill gets lost, usually because teams lift systems into the cloud without rethinking them, then wonder why costs rose and performance did not improve. This guide shows how to migrate with a strategy that actually pays off.
What is cloud migration?
Cloud migration is the process of relocating your digital operations, applications, databases, and workloads, from where they run today (on-premise data centres or another cloud) to a cloud platform. It ranges from a simple relocation of existing systems to a full modernisation that rebuilds them to take advantage of what the cloud offers.
The reason organisations migrate is to gain what the cloud does well: scaling capacity up and down on demand, paying for what you use, accessing managed services that reduce operational burden, and improving reliability and reach. But the cloud does not automatically deliver these benefits, they come from how you migrate. This is why cloud migration services focus as much on strategy and re-architecture as on the mechanics of moving.
Why do organisations migrate to the cloud?
Organisations migrate to the cloud to gain scalability, reduce the burden and cost of running their own infrastructure, and move faster. On-premise infrastructure requires buying and maintaining hardware sized for peak demand, which is expensive and slow to change. The cloud replaces that with elastic, on-demand capacity and managed services.
The concrete drivers are the ability to scale instantly with demand instead of provisioning for peak; shifting from large upfront capital to pay-as-you-go operating cost; offloading maintenance, patching, and hardware management to the provider; accessing advanced services like managed databases, analytics, and AI without building them; and improving reliability and global reach. Not every workload benefits equally, which is why the first step of any migration is deciding not just how to move, but which workloads should move and why.
What are the main cloud migration strategies?
The main migration strategies are known as the "6 Rs," and they range from moving systems as-is to rebuilding them for the cloud. Choosing the right one per workload is the core strategic decision.
| Strategy | What it means | Best for |
|---|
| Rehost | Lift and shift as-is | Speed, low-risk workloads |
| Replatform | Minor optimisations while moving | Some cloud benefit, low effort |
| Refactor | Rebuild for the cloud | Long-term value, key applications |
| Repurchase | Move to a SaaS product | Replacing systems a product covers |
| Retire | Decommission what is unused | Reducing scope and cost |
| Retain | Keep on-premise for now | Systems not ready or worth moving |
There is no single right answer; most migrations use a mix. Rehosting is fast but captures the least benefit. Refactoring captures the most but costs more effort. The skill is matching each workload to the right strategy: rehost what just needs to move, refactor what will benefit from being cloud-native, and retire what nobody uses.
How do you migrate to the cloud, step by step?
You migrate to the cloud by assessing first, moving in phases, and validating at every step, never all at once without a plan. Follow these steps.
- Define the reason. Be clear on why you are migrating and what success looks like, so choices have a yardstick.
- Assess your estate. Inventory applications and data, and map dependencies to understand what you have.
- Choose a strategy per workload. Apply the 6 Rs, deciding how each workload should move, or whether it should.
- Plan the sequence. Start with low-risk, low-dependency workloads to build confidence and learn.
- Set up the landing zone. Prepare the cloud environment with security, networking, and governance in place first.
- Migrate in phases. Move workloads in waves, validating performance and cost after each.
- Optimise after moving. Right-size, tune, and modernise once workloads are running in the cloud.
- Decommission the old. Shut down retired on-premise systems to capture the savings.
The order protects you. Assessing before moving prevents nasty surprises from hidden dependencies, and phasing means a problem affects one wave, not your whole business. The most damaging migrations skip assessment and try to move everything at once.
What are the risks of cloud migration, and how do you manage them?
The main risks of cloud migration are unexpected cost, security gaps, and downtime, and all three are manageable with planning rather than luck. They cause trouble mainly when teams migrate without assessment or rush the move.
Cost rises when workloads are lifted without right-sizing, so they run oversized in the cloud; the fix is to assess and optimise, not just relocate. Security gaps appear when the cloud environment is not configured correctly; the fix is to set up a secure landing zone with proper access controls and governance before migrating, ideally with DevSecOps practices built in. Downtime risk comes from big-bang moves; the fix is phased migration with validation and rollback plans. None of these risks is a reason to avoid the cloud; they are reasons to migrate with a plan instead of hope.
Conclusion
Cloud migration is the move of your applications, data, and workloads to the cloud for scalability, flexibility, and often lower cost, and its success depends far more on strategy than on the mechanics of moving. The organisations that gain the most treat migration as a chance to rethink and modernise, not just relocate, and they assess first, move in phases, and optimise after. The ones that struggle lift everything as-is and hope.
If you take one idea away, make it this: migrate with a reason and a plan, workload by workload. Know why you are moving, assess what you have, choose the right approach for each system, move in low-risk waves, and optimise once you land. Do that and the cloud delivers the speed, scale, and efficiency it promises. If you want help planning or running your migration, talk to our cloud team and we will build a migration plan around your estate and goals.
Key takeaways
- Cloud migration moves applications, data, and workloads to the cloud for scalability, flexibility, and often lower cost.
- The outcome depends on strategy: lifting systems without rethinking them often raises cost without the benefits.
- The main approaches are the "6 Rs," from rehosting (lift and shift) to refactoring (rebuild for cloud).
- Migration should start with a clear business reason and an assessment of what you have.
- A phased migration, starting with low-risk workloads, beats a risky all-at-once move.
- Cost, security, and downtime are the top risks, and all three are manageable with planning.
- The cloud rewards rethinking, not just relocating: the biggest gains come from modernising as you move.
