Scaling MySQL Instance

Overview

This runbook guides you through upgrading MySQL RDS instance specifications to address performance issues

When to Use This Runbook

• Persistent MySQL connection limit alerts
• High memory utilization (>80% consistently)
• CPU utilization consistently above 70%

Pre-Upgrade Checks

1. Verify Database Health
   • Recent backup available (within last 24 hours)
   • No critical alerts active
2. Choose a new instance class for mysql

Upgrade Procedure

CAUTION

This procedure will cause downtime. Coordinate with application teams and schedule during maintenance window.

Step 1: Initiate Upgrade via Console

1. Navigate to RDS Console → Databases
2. Select your DB instance
3. Click Modify
4. Under DB instance class, select new instance type
5. Apply immediately:
   • Check this box for urgent upgrades
   • Leave unchecked to apply during next maintenance window
6. Click Continue → Modify DB instance

Step 2: Monitor Upgrade Progress

1. Track upgrade status in RDS console
2. Expected downtime: 2-10 minutes depending on instance size
3. Monitor CloudWatch metrics for:
   • DatabaseConnections
   • CPUUtilization
   • FreeableMemory

Post-Upgrade Verification

Test Database Connectivity

Connect to mysql

# Test connection from application server
mysql -h <rds-endpoint> -u <username> -p<password> -e "SELECT 1;"

Validate Performance Improvements

1. Check connection limit increase:

   SHOW VARIABLES LIKE 'max_connections';

2. Monitor key metrics for 10 minutes:

   • Connection count stabilized
   • Memory utilization decreased
   • CPU utilization within normal range

Application Validation

• [ ] Application services successfully running
• [ ] No connection timeout errors