TLDR: Redis Replication Internals

Date: 2025-10-17 Source: https://arpitbhayani.me/blogs/redis-replication

Overview

One of the most fundamental design decisions in Redis replication is that it's push-based rather than pull-based. This means the master (or primary) actively sends data to replicas, rather than replicas polling the master for updates.

Key Points

• One of the most fundamental design decisions in Redis replication is that it’s push-based rather than pull-based.
• Push vs. Pull Replication: Before we explore Redis specifically, let’s establish what we mean by push and pull replication models.
• Redis Replication: To understand why push makes sense, we need to understand how Redis replication actually works.
• Why Push?: Now let’s get to the heart of the matter: why did Redis choose push-based replication?
• Trade-offs: Push-based replication has limitations: Master Resource Usage The master must maintain: For a master with many replicas (say, 100+), this can consume significant memory.