The number of I/O operations per second (IOPS) that the volume supports. For Provisioned IOPS SSD volumes, this represents the number of IOPS that are provisioned for the volume. For General Purpose SSD volumes, this represents the baseline performance of the volume and the rate at which the volume accumulates I/O credits for bursting. For more information on General Purpose SSD baseline performance, I/O credits, and bursting, see Amazon EBS Volume Types (http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSVolumeTypes.html) in the Amazon Elastic Compute Cloud User Guide.
Constraint: Range is 100-20000 IOPS for io1 volumes and 100-10000 IOPS for gp2 volumes.
Condition: This parameter is required for requests to create io1 volumes; it is not used in requests to create gp2, st1, sc1, or standard volumes.