ECU –EBS-optimized – DB instance uses an optimized configuration stack and provides additional, dedicated capacity for Amazon Elastic Block Store (Amazon EBS) I/O. This optimization provides the best performance for your Amazon EBS volumes by minimizing contention between Amazon EBS I/O and other traffic from your instance. For more information about Amazon EBS–optimized instances, go to Amazon EBS–Optimized Instances in the Amazon EC2 documentation.