System designHardsd-g215

Subject Geo replicationLevel Senior–Staff~50 minCommon in Databases & SQL · Distributed systems interviewsIndustries Technology, Software development

Question

Design an active-active geo-replicated key-value store for edge configuration (routing rules, WAF policies, rate-limit configs) served from 200+ edge POPs. Operators in any region can update config, all edges must converge to the same final state within seconds, and an edge must keep serving its last-known config even if fully partitioned from the control plane. Updates are infrequent but correctness of the final converged state is critical. How do you replicate and resolve concurrent edits?

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.