69% of organisations experience cost overruns in their cloud migration. The difference between success and failure is not the technology, but the strategy.
Migrating to the cloud is the most important infrastructure decision your company will make in the next decade. But doing it wrong can be worse than not doing it at all. In this guide we break down the 5 migration patterns, compare AWS, Azure, and GCP for Spanish SMEs, and calculate real costs with proven ROI. At ASD Solutions, our Cloud & DevOps team has completed over 40 migrations for SMEs in Spain.
Why Cloud Migrations Fail
Before talking about solutions, let's understand the 3 errors that cause 80% of cloud migration failures:
- Lift-and-shift without optimising: moving servers as-is to the cloud generates bills 40% higher than on-premise because native services are not leveraged
- Underestimating data complexity: migrating databases with cross-dependencies without a clean cutover plan causes weeks of unplanned downtime
- Ignoring the human factor: 62% of failed migrations cite lack of team training as the primary cause according to Gartner
Diagnosis: Is Your Company Ready?
Before migrating, assess these 4 dimensions with your team. If you spot more than 2 warning signs, you need a professional assessment:
| Dimension | What to ask | Warning sign |
|---|---|---|
| Applications | Do they have REST APIs or depend on legacy protocols (SOAP, RPC)? | Over 50% of apps without a modern API |
| Data | How many TB of data do you have and what maximum latency can you tolerate? | Over 10 TB without a phased migration plan |
| Infrastructure | Do you use virtualisation (VMware, Hyper-V) or bare metal? | Bare metal without configuration documentation |
| Team | Is there cloud experience on the current team? | Zero cloud certifications on the team |
5 Migration Patterns
Not all applications are migrated the same way. These are the 5 patterns recognised by AWS and Gartner, ordered from least to most effort:
- Rehost (lift-and-shift): move as-is to IaaS. Fast, low risk, 10-20% savings
- Replatform (lift-and-reshape): small adjustments to use managed services (RDS, ElastiCache). 20-35% savings
- Refactor (re-architect): redesign for cloud-native with containers and serverless. Higher effort, 40-60% savings
- Repurchase: replace legacy software with equivalent SaaS (e.g. Exchange to Microsoft 365). Technical debt elimination
- Retire: identify and shut down applications that no longer provide value. Immediate 100% savings on those workloads
Migration roadmap in 3 phases
| Phase | Duration | Objective | Deliverable |
|---|---|---|---|
| 1. Discovery | 1 week | Assessment and quick wins | App inventory, dependency map, migration plan |
| 2. Migration | 2-4 weeks | Migrate non-critical workloads + pilot | Functional cloud environment, performance metrics |
| 3. Optimisation | 1-2 weeks | Optimise costs and performance | Autoscaling, monitoring, documentation |
AWS vs Azure vs GCP for SMEs
There is no universally better cloud provider. The choice depends on your current stack, team, and business priorities:
| Criterion | AWS | Azure | GCP |
|---|---|---|---|
| Datacentre in/near Spain | Ireland, Spain (Aragon) | Spain (Madrid), Ireland | Spain (Madrid), Finland |
| Microsoft integration | Limited (WorkSpaces) | Native (Microsoft 365, Teams, AD) | Limited (Workspace) |
| GDPR | Full compliance | Full compliance + Madrid residency | Full compliance + Madrid residency |
| Partners in Spain | Largest global ecosystem | Most certified partners in Spain | Fewer local partners |
| SME pricing | Aggressive (Free Tier 12 months) | Microsoft enterprise discounts | Generous startup credits |
| Learning curve | Medium-high (200+ services) | Low if you already use Microsoft | Medium (cleaner interface) |
Real Costs and ROI
The numbers no AWS or Azure sales rep will give you. Based on 40+ real migrations of Spanish SMEs (10-100 employees):
| Savings area | Typical savings |
|---|---|
| Infrastructure (servers, network, energy) | 30-50% annually |
| Systems administration | 40-60% in hours/month |
| Availability (downtime reduction) | 50-70% in incidents |
| Software licences (managed services vs on-prem) | 20-35% in licences |
| Time-to-market (new environments) | 60-80% faster |
| Hardware renewal (3-5 year cycles) | Total elimination |
Typical break-even: 6-12 months. Average 3-year ROI: 3.86x according to Nucleus Research.
Common Mistakes
- Not setting a contingency budget: always reserve an extra 20-30% for migration surprises
- Migrating everything at once: start with non-critical workloads to learn before moving production
- Ignoring egress costs: transferring data out of the cloud can cost €0.09/GB — plan before you architect
- Not training the team: a migration without upskilling creates total dependency on the service provider
- Forgetting governance: without IAM policies, tagging, and cost alerts, the cloud bill spirals out of control in 3 months
FAQ: Cloud Migration
How much does it cost to migrate to the cloud?
Between €600 and €4,000 depending on complexity and data volume. The typical break-even is reached in 6-12 months thanks to savings on infrastructure and administration.
AWS or Azure for my company?
Azure if your company uses Microsoft 365 and Active Directory. AWS if your team has Linux experience and you want the largest catalogue of services. GCP if your focus is analytics and machine learning.
How much do you really save with cloud?
Between 30-50% on direct infrastructure costs. Total ROI, including productivity and agility, reaches 3.86x at 3 years according to Nucleus Research.
How long does a full cloud migration take?
A pilot with non-critical workloads takes 1-2 months. A full migration for a typical SME takes between 2 and 6 months following a phased approach.
Conclusion
Cloud migration is not an infrastructure project: it is a business transformation. SMEs that plan with the right patterns, choose the provider that fits their context, and train their team achieve 30-50% savings and a demonstrable ROI in under 18 months. At ASD Solutions we design realistic roadmaps, execute migrations with zero downtime, and optimise your cloud bill month after month.
