Twitter Write QPS & Tweet Storage

Easy

Twitter has 200 million DAU. On an average day, 20% of DAU post, and each poster writes 2.5 tweets. Each tweet record is ~300 bytes (id, author_id, 280-char text, timestamp, metadata).

Use: 1 day = 86,400 sec ≈ 10^5 sec. Powers of 10: 1 KB = 10^3 B, 1 MB = 10^6 B, 1 GB = 10^9 B, 1 TB = 10^12 B, 1 PB = 10^15 B.

Compute the three values below.

Back-of-envelope counts: any answer within ±30% of the target is correct, just like a real interview. Suffixes like k, M, B work.

Average write QPS (requests/sec)
requests/sec
Peak write QPS, assume 3× average (requests/sec)
requests/sec
Raw tweet storage for 5 years (TB)
TB