Best practices for Amazon DynamoDB Global Tables – Part 3: Validating regional resilience with AWS Fault Injection Service

This article explains how to use AWS Fault Injection Service (FIS) to validate DynamoDB Global Tables' resilience to regional disruptions through controlled experiments.

• AWS FIS enables testing application behavior during regional outages without real incidents
• MRSC tables: FIS pauses replication, causing 500 errors on strongly consistent reads and writes
• MREC tables: FIS blocks replication via resource policies; applications see no errors locally
• Define steady-state metrics baseline before running experiments for comparison
• Create IAM role with dynamodb:InjectError permission (MRSC) or resource policy permissions (MREC)
• Start with short 10-15 minute experiments in test environments before production
• Monitor FaultInjectionServiceInducedErrors and ReplicationLatency metrics during experiments
• Verify failover activation, alert firing, and clean recovery after experiment ends
• Automate experiments into monthly/quarterly operational readiness reviews

AWS FIS provides evidence-based validation that multi-Region DynamoDB applications handle disruptions correctly, complementing design best practices from earlier series parts.