Q39: How do you design a multi-region system?

Difficulty:AdvancedTopic:Reliability

Choose active-passive or active-active based on latency, availability, cost, and consistency needs. Route users to healthy regions, replicate data with an explicit conflict strategy, and define regional ownership and failover procedures. Active-active can reduce latency but creates write conflicts and operational complexity. Consider data residency, global identity, DNS or traffic-manager caching, dependency availability, and how to prevent split-brain during recovery.

Key Takeaways
  • Multi-region is a consistency and operations decision, not just deployment duplication.
  • Document failover, failback, and data-conflict behavior.