Indicates whether the instance is optimized for Amazon EBS I/O. By default, the instance is not optimized for EBS I/O. The optimization provides dedicated throughput to Amazon EBS and an optimized configuration stack to provide optimal I/O performance. This optimization is not available with all instance types. Additional usage charges apply. For more information, see Amazon EBS-Optimized Instances (http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSOptimized.html) in the Amazon Elastic Compute Cloud User Guide.