System designMediumsd-g206

Subject Conflict resolutionLevel Mid–Senior~35 minCommon in Distributed systems interviewsIndustries Technology, Software development

Question

Design the write path for a multi-master user-preferences store (theme, notification settings, feature flags per user) replicated across 5 regions, where any region can accept a write and writes are async-replicated. The product accepts eventual consistency. The team wants to resolve concurrent conflicting writes with last-write-wins. What are the failure modes of LWW here, and when is it actually the right choice?

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.