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HardPrep Room Coding #3705

Object storage service

System designDatabases & SQLStorage & CDNSenior–Staff~45 min

Design an S3-like object-storage service. Constraints: 11 nines (99.999999999%) of durability, exabyte-scale total capacity, objects from 1 KB to 5 TB, read-heavy at roughly 20:1 read/write, p99 GET latency under 100 ms for warm objects, and strong read-after-write consistency for new PUTs. Walk the request path, the metadata layer, and how you place and protect bytes at this scale.

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.

Clarify5:00 left
Estimate5:00 planned
Design15:00 planned
Deep dive12:00 planned
Failure8:00 planned
0:00
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.