System designHardsd-g719

Subject StorageLevel Senior–Staff~45 minCommon in Storage & CDN · Distributed systems interviewsIndustries Technology

Question

Design the metadata service for a distributed filesystem (HDFS/GFS-style): the system stores huge files as fixed-size blocks replicated across thousands of data nodes, but a single namespace must track the directory tree, file→block mappings, and block→replica locations. Clients do path lookups, opens, and renames; the metadata layer must be fast, consistent, and not become a single point of failure. How do you design it?

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.