Challenge 10: Capstone: home timelines
Users post 1,000 times a second and read their home timelines, which are personal to each of them, 19,000 times a second. Each post goes to 100 followers' timelines on average. Building a timeline from the post store takes 10 reads. Survive the loss of any instance with p99 under 250 ms, for at most 5,000 USD a month.
Traffic demand20,000 RPS95% reads, 5% writes
p99 latency target≤ 250 msSlowest 1% of requests
Availability≥ 99.99%N-1 failure survival (0 drops)
Monthly cloud budget≤ 5,000 USDA month, everything included