Explanation: Provisioned IOPS volumes are designed to meet the needs of I/O-intensive workloads, particularly database workloads that are sensitive to storage performance and consistency in random access I/O throughput. A provisioned IOPS volume can range in size from 10 GB to 1 TB and the user can provision up to 4000 IOPS per volume.
The ratio of IOPS provisioned to the volume size requested can be a maximum of 30; for example, a volume with 3000 IOPS must be at least 100 GB.
Reference:
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSVolumeTypes.html