Code Room
System designHardsd-g724
Subject Object storageLevel Senior–Staff~40 minCommon in Storage & CDN · Concurrency interviewsIndustries Technology

Question

Design a WORM (write-once-read-many) compliance object store for regulated records (financial/legal): once written, an object must be immutable and undeletable until its retention period expires — provably, even against a privileged administrator or the storage vendor — with optional indefinite legal holds. Records range from KB documents to GB archives, durability must be eleven-nines, and auditors require tamper-evident proof. How do you enforce immutability and retention you can't bypass?

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.

Narrate your design
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Run or narrate your approach, then ask the coach.