System design interview question
Design a Distributed Global DNS Resolution and Traffic Management System like AWS Route 53 at Scale
Design a globally distributed DNS resolution service that handles 1 million queries per second across 200+ countries with sub-100ms latency, supports multiple routing policies (latency-based, weighted, failover, geolocation), and provides real-time health checking with automatic failover. The system must handle zone management for 10 million domains, maintain 99.99% availability, support DNSSEC, and efficiently cache responses while managing cache coherency across geographically distributed nameservers. Consider how you'd architect the control plane for domain management, data plane for query processing, the health checking infrastructure, and how you'd handle DDoS mitigation at DNS layer.
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