Hard Design: News Feed (Facebook/Twitter)

What is 'fan-out on write' in the context of a news feed?

— Tests your understanding of this concept.

Answer Options

A Writing to multiple databases simultaneously

B When a post is created, immediately updating all followers' feed caches

C Distributing read traffic across servers

D Writing media to multiple CDN nodes

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This question is from the Design: News Feed (Facebook/Twitter) topic (System Design Cases).

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