System designHardsd-g523

Subject Messaging queuesLevel Senior–Staff~50 minCommon in Storage & CDN · Distributed systems interviewsIndustries Technology, Software development

Question

Design the storage layer of a high-throughput append-only log broker. Requirements: sustain 2GB/s writes across partitions, retain data for 30 days but keep hot recent data fast, support replaying from any offset, replicate for durability, and support 'compacted' topics where only the latest value per key is retained. Disk is the bottleneck and you must keep per-partition cost low.

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.