System designHardsd-g066

Subject Load balancingLevel Senior–Staff~45 minCommon in Networking & APIs interviewsIndustries Technology, Software development

Question

Design global traffic management for a service running in 8 regions worldwide. You must route each user to a healthy nearby region, fail traffic away from a region that goes down within seconds, drain a region for maintenance gracefully, and avoid sending a user to a far region just because it's marginally less loaded. Compare DNS-based vs anycast routing, and explain the failover and drain mechanics.

What a strong answer looks like

Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts — data model, bottlenecks, consistency, failure modes — and name the trade-offs you are making.

Learn the concepts

Narrate your design

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Run or narrate your approach, then ask the coach.