System design interview question
Design a Real-time Activity Feed System with Multi-Tenant Support (Similar to LinkedIn Feed)
Design a distributed activity feed system serving 500M users globally, where each user follows 0-5000 other users and generates up to 10 events per day (status updates, likes, comments, shares). The system must support 50K read requests/sec and 5K write requests/sec with sub-500ms latency at p99 for feed generation. Users expect personalized feeds that include activities from their followers, ranked by relevance and recency, with support for filtering by content type. The system must handle geographic distribution across 3 regions, maintain eventual consistency for non-critical ranking changes, and scale elastically during peak hours (2x normal load).
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