On-Premise to AWS Migration: Complete Cloud Migration Guide 2025

• Automated infrastructure discovery (servers, databases, storage, network)
• Application dependency mapping and communication patterns
• Performance baseline and resource utilization analysis
• AWS service recommendations and cost estimation

• AWS account setup with Organizations and multi-account strategy
• VPC design with subnets, routing, and security groups
• Hybrid connectivity setup (VPN or Direct Connect)
• IAM roles, policies, and security baseline configuration

• Initial data transfer using AWS DataSync or Snowball (for large datasets)
• Database migration with continuous replication (DMS or AI agents)
• File server migration to S3/EFS with sync validation
• Data integrity verification and reconciliation

• Server replication using AWS Application Migration Service
• Application configuration updates for AWS environment
• Testing in AWS with production-like workloads
• Performance tuning and optimization

• Final data synchronization and consistency check
• DNS cutover with gradual traffic migration
• 24/7 monitoring and support during transition period
• Cost optimization and right-sizing recommendations

Challenge: Transferring large datasets (10TB+) over internet can take weeks or months.

AI Solution: Intelligent transfer strategy selection based on data size. For datasets under 10TB, uses optimized network transfer with compression and parallel streams. For 10-80TB, recommends AWS Snowball Edge. For 80TB+, recommends AWS Snowmobile. Automatically handles incremental sync after initial transfer. Optimizes transfer windows during off-peak hours.

Result: 10TB transferred in 2-3 days vs 4-6 weeks over standard internet.

Challenge: Legacy applications may have undocumented dependencies or require specific OS versions.

AI Solution: Automated dependency discovery through network traffic analysis and system call monitoring. Identifies all inter-application communication, shared libraries, and external dependencies. Recommends compatible AWS instance types and OS versions. Flags incompatible components for refactoring or replacement. Generates migration runbook with dependency order.

Result: 95% of dependencies automatically discovered and mapped.

Challenge: On-premise licenses may not transfer to cloud, and cloud costs can spiral without optimization.

AI Solution: Analyzes existing licenses for cloud portability (BYOL programs). Recommends cost-effective alternatives (open-source, AWS-native services). Right-sizes instances based on actual usage patterns, not peak capacity. Implements auto-scaling and spot instances where appropriate. Provides 3-year TCO comparison with optimization recommendations.

Result: 40-60% lower ongoing costs vs on-premise, 30% savings vs unoptimized cloud.

Challenge: Must maintain security posture and compliance certifications during and after migration.

AI Solution: Maps on-premise security controls to AWS equivalents. Implements AWS security best practices (encryption at rest/transit, IAM least privilege, VPC isolation, CloudTrail logging). Maintains compliance with industry standards (PCI-DSS, HIPAA, SOC 2). Provides continuous compliance monitoring and automated remediation. Generates compliance reports for auditors.

Result: Security posture maintained or improved, all compliance requirements met.

With AI-powered automation, on-premise to AWS migration typically takes 4-6 weeks for most enterprise workloads. Traditional manual migration can take 6-18 months. Timeline depends on data volume, application complexity, and number of servers. Simple migrations (single application, small database) can complete in 2-3 weeks, while complex multi-tier applications with large datasets may take 8-12 weeks. The 7R migration strategies (Rehost, Replatform, Refactor, Repurchase, Retire, Retain, Relocate) affect timeline - lift-and-shift (Rehost) is fastest, while refactoring takes longer but provides better cloud optimization.

Yes, zero-downtime migration to AWS is achievable for most applications using continuous replication and gradual cutover. The approach involves setting up parallel AWS infrastructure, establishing real-time data replication from on-premise to AWS, running both environments simultaneously during transition, and gradually shifting traffic using DNS or load balancer updates. Database migrations use continuous replication (AWS DMS or AI agents) to keep on-premise and AWS databases in sync. Applications are tested in AWS before cutover. Most organizations experience less than 5 minutes of planned downtime during final DNS cutover.

AI-powered on-premise to AWS migration costs 75% less than manual migration. For a typical 100-server, 50TB environment, expect $150,000-$300,000 for automated migration vs $600,000-$1,200,000 for manual. Major cost factors include data transfer (AWS DataSync or Snowball), migration tooling, temporary dual-environment operation, and professional services. However, ongoing AWS costs are typically 40-60% lower than on-premise TCO when properly optimized (no hardware refresh, reduced datacenter costs, pay-as-you-go pricing, auto-scaling). AWS Migration Acceleration Program (MAP) provides funding to offset migration costs.

Start with lift-and-shift (Rehost) for speed, then refactor incrementally for optimization. Lift-and-shift moves applications to AWS with minimal changes, completing migration in 4-6 weeks and immediately reducing datacenter costs. After migration, refactor applications to use cloud-native services (RDS instead of self-managed databases, S3 instead of file servers, Lambda for batch jobs) for better performance, scalability, and cost optimization. This two-phase approach balances speed and optimization. Refactor first only for applications with major technical debt or those requiring significant changes anyway.

For Active Directory, use AWS Directory Service to extend on-premise AD to AWS or create managed AD in AWS. Options include: (1) AD Connector for simple proxy to on-premise AD, (2) AWS Managed Microsoft AD for standalone cloud AD with trust to on-premise, (3) Simple AD for basic LDAP needs. For Windows licensing, use License Mobility through Software Assurance to bring existing licenses to AWS (BYOL), or use AWS-provided Windows licenses (License Included). SQL Server can use BYOL or License Included options. AI migration tools automatically identify Windows servers and recommend optimal licensing strategy based on your existing agreements.