System designHardsd-g082

Subject Inverted indexLevel Senior–Staff~50 minCommon in Databases & SQL interviewsIndustries Technology

Question

Design a log-search system ingesting 2M log lines/sec (5TB/day) where engineers run ad-hoc full-text + structured-field queries over a time range. Recent data (last 24h) must be queryable within seconds of ingestion; older data (up to 30 days) can tolerate slower queries. Cost must stay bounded, so storage tiering is required.

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.