What is Auto Scaling?

Aurora automatically adds or removes Read Replicas based on how busy your database is.

How It Works

Client sends many requests
        ↓
Reader Endpoint notices high CPU usage
        ↓
Aurora automatically adds more replicas
        ↓
Reader Endpoint extended (now has more replicas)
        ↓
Load distributed across all replicas
        ↓
When traffic decreases, Aurora removes extra replicas

Key Points

Monitoring:

• Monitors CPU usage on existing replicas
• Tracks database workload continuously

Scaling Up:

• When CPU is high → Adds more replicas automatically
• Can scale up to 15 read replicas

Scaling Down:

• When CPU is low → Removes replicas to save money
• Optimizes cost based on actual usage

Load Balancing:

• Reader Endpoint automatically load-balances across all replicas
• All replicas share the same storage (reads and writes)

Benefits