Overview

Amazon ElastiCache is more than just an in-memory data store — it’s a highly available, secure, and intelligent caching platform that powers low-latency, real-time applications at scale.

In this blog, we’ll cover:

• Redis Cluster Mode vs Non-Cluster Mode
• Replication and Failover
• ElastiCache Security (IAM, Redis AUTH, SSL)
• Caching Patterns (Lazy, Write-Through, Session Store)
• Real-Time Leaderboard Use Case

1. Redis Cluster Mode vs Non-Cluster Mode

Cluster Mode Disabled (Non-Cluster Mode)

• Single primary node with up to 5 replicas
• Replication is asynchronous
• Automatic failover to replica on primary failure
• Simpler setup — ideal for smaller workloads or dev environments

Architecture Example

[Primary Node] → [Replica 1]
                 [Replica 2]

Failover:

If primary fails → replica promoted to primary automatically.