Code Room
System designHardsd-g498
Subject Blob storeLevel Senior–Staff~45 minCommon in Databases & SQL · Storage & CDN · Distributed systems interviewsIndustries Technology, Software development

Question

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.

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