Cross-region blob replication
Design cross-region replication for a large-media object store where multi-GB objects (video masters, datasets) written in one region must be asynchronously replicated to 2–3 other regions for durability and low-latency local reads, at a rate of 100 GB/s of new writes globally. Replication must be efficient (don't re-ship unchanged data on overwrite), must not lose objects if a region is destroyed, and readers in a remote region need clear semantics about whether they'll see the latest version yet.
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
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.