Migration Assessment

AWS provides a comprehensive suite of tools for discovering and assessing on-premises workloads before migration. Understanding these tools is critical for building accurate migration plans that minimize risk and optimize costs.

AWS Migration Hub serves as the central console for tracking migration progress across multiple AWS and partner tools. It provides a unified view of all applications being migrated, their current status, and associated tasks. Migration Hub organizes applications into portfolios and tracks them through phases: discovered, assessed, mobilized, migrated, and modernized. For example, a company migrating 50 applications can track each one's progress from initial discovery through production deployment in a single dashboard.

AWS Application Discovery Service (ADS) automates the collection of detailed information about on-premises data centers. ADS offers two discovery methods:

Agentless discovery uses the AWS Application Discovery Agentless Collector, a VMware-based appliance that captures performance data without installing agents on each server. This method is ideal for VMware environments where you need minimal disruption. The collector gathers CPU, memory, disk, and network utilization data over a specified period, typically 2-4 weeks, to establish baseline performance patterns.

Agent-based discovery requires installing the AWS Application Discovery Agent on each server you want to assess. The agent provides more detailed data including running processes, network connections between servers, and system performance metrics. It captures process-level dependency information, showing exactly which services communicate with each other. For a financial services company, agent-based discovery might reveal that their trading application communicates with 12 internal services and 3 external APIs.

Server Migration Service (SMS) integrates with ADS to provide server-level assessment data. It captures volume information, operating system details, and application dependencies. SMS can also perform test migrations, creating temporary EC2 instances to validate that servers will function correctly in the AWS environment.

The discovery process typically runs for 2-4 weeks to capture representative workload patterns, including peak usage periods, batch processing windows, and seasonal variations. The collected data feeds directly into the 6 Rs classification process and informs infrastructure sizing for the target AWS environment.

Dependency mapping is the process of identifying and documenting relationships between applications, databases, middleware, and infrastructure components. Accurate dependency maps are essential for sequencing migrations, identifying risks, and designing target architectures.

Network dependency mapping identifies which servers communicate with each other and through which ports and protocols. AWS ADS agent-based discovery captures this data automatically, building a visual map of your application ecosystem. For example, you might discover that your customer portal depends on three microservices, two databases, and an external payment gateway.

Database dependencies are particularly important because database migrations are often the highest-risk component of cloud migration. Map which applications connect to each database, what query patterns they use, and what data volumes exist. A healthcare system might discover that 15 different applications query a central patient database, requiring careful coordination during database migration to minimize downtime.

Business case development translates technical assessment data into financial justification for migration. The business case should quantify both tangible and intangible benefits:

Cost savings include reduced hardware purchases, lower licensing fees, decreased facilities costs, and operational efficiency gains. Use the AWS TCO Calculator to model infrastructure cost comparisons. A typical enterprise might achieve 30-40% infrastructure cost reduction through right-sizing and using reserved instances.

Revenue enablement captures how cloud migration enables new capabilities: faster time-to-market, global reach, improved scalability, and enhanced developer productivity. These benefits are harder to quantify but often exceed direct cost savings.

TCO Analysis should account for all costs over a 3-5 year period. Include migration project costs (labor, tools, consulting), ongoing cloud costs (compute, storage, networking), operational changes (staff training, new processes), and transition costs (dual running during migration). The analysis should present scenarios: optimistic, realistic, and conservative.

The business case document should include an executive summary, current state assessment, proposed migration approach, financial analysis with NPV and ROI calculations, risk assessment, and recommended timeline.