Multi-Region Failover Strategies
Issue #117: System Design Interview Roadmap • Section 5: Reliability & Resilience
When Entire Data Centers Go Dark
When Hurricane Sandy flooded a significant portion of AWS's US-East-1 data center in 2012, thousands of applications running single-region architectures went offline for hours. Netflix, however, continued streaming to millions of users without interruption. The difference? Their multi-region failover strategy treated regional failures as routine events, not catastrophes.
Today, we'll explore the sophisticated patterns that keep global applications running when entire regions disappear, and build a working system that demonstrates these principles in action.
What You'll Master Today
Active-Passive vs Active-Active strategies and their hidden trade-offs
DNS-based failover mechanics with real latency implications
Data consistency challenges during cross-region operations
Network partition detection and automated recovery patterns
Enterprise-grade monitoring for multi-region health assessment