Distributed block storage
Design an EBS-like distributed block-storage service that presents network-attached virtual disk volumes to VMs. Each volume must look like a local block device, survive single-disk and single-host failures with 99.999% durability, deliver low-tail-latency 4KB random I/O, and support snapshots. A volume attaches to exactly one VM at a time. How do you lay out data, replicate it, and handle a host failure without corrupting the volume?
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.