System designHardsd-g596

Subject Ml system design llm ragLevel Senior–Staff~55 minCommon in ML systems · Distributed systems interviewsIndustries Technology

Question

Design a retrieval-augmented LLM system that answers questions over a company's 10M-document knowledge base for 50k employees, with a 3s p95 end-to-end budget, answers grounded in (and citing) source documents, freshness within minutes of a document changing, and strict access control so users only see content they're authorized for. Cover ingestion/indexing, the retrieval + generation path, how you enforce permissions and freshness, and how you evaluate answer quality.

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.