Title

AWS re:Invent 2022 - Multi-Region design patterns and best practices (ARC306)

Summary

• John Fermento introduced the session, emphasizing the importance of understanding multi-region requirements and not all applications need multi-region architecture.

• Multi-region fundamentals were discussed, including:

  • Understanding requirements through business and IT alignment via tiering strategies.
  • Understanding data, particularly the implications of asynchronous vs. synchronous replication.
  • Understanding dependencies, ensuring services are available in the target region, and considering third-party dependencies.
  • Failover mechanisms should be independent of the primary region.
  • Operational readiness, including service quotas, IAM permissions, and service control policies.
  • Deployment strategies should avoid simultaneous deployments across regions.
  • Monitoring and observability are crucial, especially for replication lag and health of the application in the primary region.
  • People and process, including regular testing of the DR strategy and defining the scope of failover.
  • Cost and complexity considerations, as multi-region can be expensive and complex.

• Barry Sheward from Vanguard Group shared their global multi-region strategy, focusing on:

  • Improving user experience by moving compute and data closer to users.
  • High availability without significant user impact during failures.
  • Data patterns like hub and spoke, and follow the sun.
  • Dependencies on third-party data providers and how they handle them using AWS services.
  • Operational readiness through continuous testing and anomaly detection.

• Neeraj Kumar discussed broader multi-region patterns, including:

  • Active-passive for regional failover and regulatory needs.
  • Active-active for high availability and performance needs.
  • Regional sharding for data locality and performance.
  • Single writer and multiple readers for eventual consistency.
  • Strong consistency across regions for zero RPO requirements.
  • Dual writes for data atomicity and idempotency.
  • Multi-writers, multi-readers for distributed read and write traffic.
  • Routing strategies using DNS, Lambda at Edge, and Global Accelerator.
  • Key takeaways: start with single-region resilience, consider business value, avoid inter-region dependencies, and choose the right pattern for your workload.

Insights

• Multi-region architecture is not a one-size-fits-all solution and should be considered based on specific business needs and application requirements.
• Asynchronous replication is preferred for performance but comes with the risk of data not being immediately available in the standby region, while synchronous replication ensures data consistency but introduces latency.
• Dependencies on third-party services can be a significant risk factor in multi-region architectures, and strategies should be in place to mitigate this risk, such as using multiple providers or ensuring they can operate independently.
• Operational readiness is critical, and regular testing of disaster recovery strategies is essential to ensure they will work when needed.
• Cost and complexity are significant factors in multi-region deployments, and the benefits must be weighed against these considerations.
• Routing strategies can be complex in active-active scenarios, and services like AWS Lambda at Edge and Global Accelerator can provide advanced routing capabilities.
• Resilience can often be improved within a single region before considering multi-region, which should be a strategic decision rather than a default approach.