Code RoomMulti-master preferences conflict resolution
MediumPrep Room Coding #3329

Multi-master preferences conflict resolution

System designDistributed systemsMid–Senior~35 min

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.

Clarify4:00 left
Estimate4:00 planned
Design11:30 planned
Deep dive9:30 planned
Failure6:00 planned
0:00
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.