Observability dashboard serving
Design the query/serving backend for an observability dashboarding product. A popular incident dashboard has 40 panels, each running a metrics query, and during an outage 500 engineers all load it at once, hammering the metrics backend with 20,000 near-identical queries in seconds. Dashboards auto-refresh every 30s. The metrics backend is the bottleneck and starts to brown out. Design the serving layer so dashboards stay fast and the backend survives the thundering herd.
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.
Clarify4:00 left
Estimate4:00 planned
Design11:30 planned
Deep dive9:30 planned
Failure6:00 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.