What is Cloud Migration?
Cloud migration is the process of moving applications, data, workloads, and IT infrastructure from on-premises data centers to cloud platforms like AWS, Azure, or Google Cloud. It can also involve moving between cloud providers or consolidating data centers.
Quick Answer
Cloud migration improves scalability, reduces infrastructure costs by 30-50%, increases agility, and enables modern DevOps practices. Organizations migrate to eliminate data center management, scale on demand, improve disaster recovery, and accelerate innovation.
Types of Cloud Migration
On-Premises to Cloud
Most common migration type. Move from physical data centers or colocation facilities to AWS, Azure, or Google Cloud. Eliminates hardware management, reduces costs, improves scalability.
Cloud-to-Cloud
Migrate between cloud providers (AWS to Azure, Azure to GCP, etc.) or consolidate multiple cloud accounts. Driven by cost optimization, feature requirements, or vendor consolidation.
Hybrid Cloud
Partial migration keeping some workloads on-premises while moving others to cloud. Common for regulatory requirements, legacy systems, or gradual migration approach.
The 6 Rs: Cloud Migration Strategies
1. Rehost (Lift-and-Shift)
Move applications as-is without changes. Fastest, lowest risk approach.
- Timeline: 3-6 months
- Cost: Lowest upfront ($50K-$150K)
- Best for: Quick migration, minimal business disruption
- Limitation: Doesn't leverage cloud-native benefits immediately
2. Replatform (Lift-and-Reshape)
Minor optimizations without changing core architecture. Balance of speed and cloud benefits.
- Timeline: 6-9 months
- Cost: Moderate ($100K-$300K)
- Best for: Some optimization without full refactor
- Example: Move to managed database (RDS instead of self-managed)
3. Refactor (Rearchitect)
Redesign for cloud-native architecture. Maximum cloud benefits, highest effort.
- Timeline: 9-18 months
- Cost: Highest ($200K-$1M+)
- Best for: Mission-critical apps needing scalability
- Example: Containerize with Kubernetes, serverless, microservices
4. Repurchase (Drop-and-Shop)
Move to SaaS instead of hosting yourself. Reduces operational burden.
- Timeline: 3-6 months (including migration)
- Cost: Subscription-based, varies widely
- Best for: Standard business applications (CRM, HR, email)
- Example: Move Exchange to Microsoft 365, SAP to Workday
5. Retire
Decommission applications no longer needed. Immediate cost savings.
- Identify during discovery phase
- Typically 10-20% of portfolio can be retired
- Archive data if needed for compliance
6. Retain (Revisit)
Keep on-premises for now. Migrate later or not at all.
- Legacy systems too costly to migrate
- Regulatory requirements preventing cloud
- Recently upgraded systems with sunk costs
Cloud Migration Process
Phase 1: Assessment & Planning (4-8 weeks)
- Inventory all applications, databases, and dependencies
- Assess current performance, costs, and requirements
- Determine migration strategy for each application (6 Rs)
- Calculate total cost of ownership (TCO) on-premises vs cloud
- Create migration roadmap and wave plan
- Identify risks and mitigation strategies
Phase 2: Proof of Concept (4-6 weeks)
- Migrate 1-2 non-critical applications as pilot
- Validate migration approach and tooling
- Test performance, security, and operations
- Refine migration playbooks based on learnings
- Train team on cloud operations
Phase 3: Migration Waves (8-40 weeks)
- Execute migrations in batches (waves) of related applications
- Start with least complex, build expertise
- Migrate data using appropriate tools (AWS DMS, Azure Migrate)
- Configure cloud networking, security, and monitoring
- Test thoroughly before cutover
- Execute cutover during maintenance window
Phase 4: Optimization (Ongoing)
- Right-size instances based on actual usage
- Implement auto-scaling and reserved instances
- Optimize storage tiers and data lifecycle
- Leverage managed services to reduce operations
- Continuous cost monitoring and optimization
Timeline by Complexity
Small/Simple (3-6 months):
5-20 applications, mostly rehost, single location | $50K-$150K
Medium Complexity (6-12 months):
20-100 applications, mixed strategies, some legacy dependencies | $150K-$400K
Large Enterprise (12-18+ months):
100+ applications, global locations, complex dependencies, regulatory requirements | $400K-$2M+
Cost Breakdown
- Assessment & Planning: $10K-$50K (consultants, tools)
- Migration Execution: $30K-$300K (labor, tools, testing)
- Testing & Validation: $10K-$75K (performance, security testing)
- Training: $5K-$25K (cloud operations, new tools)
- Ongoing Cloud Costs: Typically 30-50% less than on-premises after optimization
- Migration Tools: $5K-$50K (CloudEndure, Azure Migrate, etc.)
Benefits
- 30-50% infrastructure cost reduction (after optimization)
- Instant scalability without hardware procurement
- 99.9%+ availability and built-in disaster recovery
- 40-60% faster deployment through automation
- Global reach with 25+ regions and edge locations
- Improved security with cloud-native tools and compliance
- Pay-per-use pricing, no capital expenditure
- Faster innovation with managed AI/ML, analytics, containers
- Eliminate data center management burden
- Better business continuity and disaster recovery
Common Risks & Mitigation
Cost Overruns
Risk: Cloud costs exceed projections by 40-60%
Mitigation: Right-sizing before migration, implement cost monitoring, use reserved instances, enable auto-shutdown for non-prod
Performance Issues
Risk: Applications run slower in cloud
Mitigation: Performance testing before cutover, proper instance sizing, optimize database configurations, use CDN for global apps
Security Gaps
Risk: Misconfigured cloud resources create vulnerabilities
Mitigation: Security review before migration, use cloud security posture management (CSPM), implement least-privilege access, enable logging
Skills Gap
Risk: Team lacks cloud expertise for operations
Mitigation: Training programs, cloud certifications (AWS, Azure), hire cloud engineers, use managed services to reduce complexity
Choosing a Cloud Provider
- AWS: Most mature, broadest service catalog, best for startups and tech companies
- Azure: Best Microsoft integration, strong for enterprises with Windows/AD
- Google Cloud: Best for data analytics, AI/ML, Kubernetes
- Multi-Cloud: Avoid vendor lock-in but adds complexity (only if required)
Expert Cloud Migration Support
Pilotcore provides end-to-end cloud migration services from assessment through optimization. Our certified cloud architects (AWS, Azure, GCP) have migrated 200+ applications across 50+ organizations, reducing costs by 40% on average.
