Unit 4: Accelerate Workload Migration and Modernization

This study guide covers Domain 4 of the AWS Certified Solutions Architect - Professional (SAP-C02) exam, focusing on the strategic assessment, execution, and modernization of workloads during their transition to AWS.

Learning Objectives

After studying this guide, you should be able to:

• Assess existing application portfolios and prioritize them for migration using wave planning.
• Select the most appropriate migration strategy from the "7Rs" framework.
• Evaluate Total Cost of Ownership (TCO) and migration readiness.
• Implement data and application migration using services like AWS MGN, DMS, and DataSync.
• Architect new cloud-native environments for legacy workloads using containers and serverless technologies.
• Establish a Cloud Center of Excellence (CCoE) and utilize a Cloud Migration Factory approach.

Key Terms & Glossary

• 7Rs: The seven common migration strategies (Rehost, Replatform, Relocate, Refactor, Repurchase, Retain, Retire).
• Cloud Migration Factory: A structured, repeatable approach to migrating applications at scale using automation and standardized patterns.
• Wave Planning: The process of grouping applications into logical "waves" based on complexity and dependencies to ensure a smooth migration timeline.
• Landing Zone: A well-architected, multi-account AWS environment that is the starting point for any migration.
• TCO (Total Cost of Ownership): A financial estimate intended to help buyers determine the direct and indirect costs of a product or system, comparing on-premises to cloud costs.

The "Big Idea"

Migration is not a single event but a three-phase journey: Assess, Mobilize, and Migrate/Modernize. The goal is to move from a rigid on-premises infrastructure to a flexible, scalable cloud environment. Success depends less on the "move" itself and more on the governance (CCoE), automation (Migration Factory), and modernization (Refactoring) that allow an organization to realize the full business value of AWS.

Formula / Concept Box

Hierarchical Outline

1. Portfolio Assessment (Task 4.1)
   • Inventory Discovery: Using AWS Application Discovery Service.
   • Prioritization: Low-hanging fruit vs. mission-critical apps.
   • TCO Analysis: Comparing CapEx (on-prem) to OpEx (AWS).
2. Migration Execution (Task 4.2)
   • Server Migration: AWS Application Migration Service (MGN).
   • Database Migration: AWS DMS and Schema Conversion Tool (SCT).
   • Data Transfer: Snow Family (offline), DataSync (online), Transfer Family (SFTP).
3. New Architecture (Task 4.3)
   • Compute Selection: EC2 vs. Lambda vs. Fargate.
   • Storage Selection: EFS (shared) vs. EBS (block) vs. S3 (object).
4. Modernization (Task 4.4)
   • Containerization: ECS and EKS for microservices.
   • Serverless: Using EventBridge and Step Functions for orchestration.

Visual Anchors

The Migration Process Flow

Data Transfer Decision Matrix

Definition-Example Pairs

• AWS SCT (Schema Conversion Tool): A tool that converts database schemas from one engine to another (e.g., Oracle to Aurora).
  • Example: A financial firm wants to move from an expensive licensed SQL Server to Amazon Aurora; SCT identifies which stored procedures need manual rewriting.
• AWS Application Migration Service (MGN): The primary service for lifting and shifting physical, virtual, or cloud servers to AWS.
  • Example: A company needs to vacate a data center in 30 days and uses MGN to replicate 200 Windows servers at the block level.

Worked Examples

Problem: Determining the Migration Path

A company has a legacy Java application running on a monolithic server with a local MySQL database. They want to reduce operational overhead but cannot rewrite the code immediately.

Step-by-Step Breakdown:

1. Evaluate Strategy: Since code change is not an option, Refactor is out. Rehost is possible but doesn't reduce DB management overhead.
2. Select Strategy: Replatform is the best choice.
3. Application Step: Use AWS MGN to move the Java app to an EC2 instance in an Auto Scaling Group.
4. Database Step: Use AWS DMS to migrate the local MySQL data to Amazon RDS for MySQL.
5. Result: The application remains largely the same, but the database is now a managed service, reducing "undifferentiated heavy lifting."

Checkpoint Questions

1. What tool is used to automate the replication of source servers to AWS at the block level? (Answer: AWS MGN)
2. When migrating a database with a different engine (e.g., Oracle to PostgreSQL), which two tools are typically used together? (Answer: AWS SCT and AWS DMS)
3. Which migration strategy involves moving an application to a new cloud-specific platform without changing the core code? (Answer: Replatforming)
4. What is the role of a Cloud Center of Excellence (CCoE)? (Answer: To standardize patterns, provide guidance, and eliminate migration barriers across the organization.)

Muddy Points & Cross-Refs

• MGN vs. DMS: Remember that MGN is for the entire server (OS, Apps, Disk), while DMS is specifically for data inside a database or S3.
• DataSync vs. Snow Family: Use DataSync if you have sufficient bandwidth and a continuous stream; use Snow Family if you have huge datasets (PB scale) and limited internet connectivity.
• Cross-Ref: For deeper architecture details, see Domain 2: Design for New Solutions regarding how to pick the right database type (SQL vs. NoSQL).

Comparison Tables