System designHardsd-g056

Subject CdnLevel Senior–Staff~45 minCommon in Storage & CDN interviewsIndustries Technology, Software development

Question

Design CDN delivery for large software/game updates (5–50 GB files) downloaded by tens of millions of users in a few hours after a release. Most users download the same files, downloads must resume after interruption, and a single file is too big to fully fit on every edge node. Origin bandwidth is the bottleneck. Design segmentation, edge caching, and how you keep origin from being crushed on release day.

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.

Learn the concepts

Narrate your design

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Run or narrate your approach, then ask the coach.