S3-compatible object storage
Design the object-storage API and metadata layer for an S3-compatible service used heavily for media: multipart uploads of multi-GB objects, strong read-after-write so a client that uploads then immediately reads gets the new bytes, range reads for video seeking, and integrity guarantees (a corrupted byte must be detectable). Design the API surface, how multipart upload finalizes consistently, and how reads see a coherent view under concurrent overwrites.
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.
Clarify4:30 left
Estimate4:30 planned
Design13:30 planned
Deep dive10:30 planned
Failure7:00 planned
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.