System design interview questionEasyBasic System Component
Design a Content Delivery Network (CDN)
Design a CDN: cache content at the edge so users download from a nearby PoP instead of always hitting origin.
Interview scope
Client → CDN. Origin behind CDN via Object Storage and/or LB → App. Draw Client → CDN (required).
Functional requirements
- Serve cached static/media objects to clients.
- Fetch from origin on cache miss.
- Support many edge locations at a high level.
Scale and quality goals
- Low latency for viewers far from origin.
- Origin must not take every hit at global scale.
- Large objects live in object storage / origin backends.
Capacity assumption
Design for this scale
Assume ~1B object requests/day (~12k RPS average) with a high cache-hit ratio at the edge.
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