Automatically scale storage for Amazon RDS Multi-AZ DB clusters using AWS Lambda

This article presents an automated storage scaling solution for Amazon RDS Multi-AZ DB clusters using AWS Lambda, CloudWatch, and SNS.

• RDS Multi-AZ clusters with readable standbys lack native storage auto-scaling capability
• CloudWatch monitors FreeStorageSpace metric and triggers Lambda when threshold breached
• Lambda automatically scales storage by configurable percentage (default 15%)
• Solution deployable via CloudFormation template or manual AWS console setup
• Supports monitoring multiple databases through comma-delimited parameters
• Customizable scaling percentages for different database environments
• SNS delivers notifications when scaling events occur
• RDS enforces 6-hour minimum between storage modifications
• Solution is Region-specific; deploy separately for multi-Region deployments

This automation eliminates manual storage scaling overhead while preventing database unavailability from storage exhaustion.