High Availability for Social Media Platforms: Leader-Follower Architecture and Leader Election

Leader - Follower Architecture

Imagine you are the owner of a social media company. You know that database read access is very high, with billions of users scrolling through posts and feeds. On the other hand, the number of users adding posts is comparatively low, meaning write access is much less frequent. Because your platform is used worldwide, minimising latency is essential. One way to achieve this is by using a leader-follower architecture. Here, the leader database handles all write requests (e.g., users posting new content), while multiple follower databases replicate the leader in real time and serve all read requests (e.g., users scrolling). The followers keep themselves up to date with the leader database (they update their data with leaders) with minimal latency.

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