I don't know how Amazon Elastic Block Store (Amazon EBS) io2 Block Express volumes differ from io1 and io2 volumes. Can you explain the difference between the volume types?
io1, io2 and io2 Block Express are all Provisioned IOPS SSD volumes. However, io2 Block Express volumes can deliver higher throughput and IOPS, and support larger capacity. For more information on each volume type, see the Provisioned IOPS SSD comparative chart.
io2 Block Express volumes are attached to the following supported Amazon Elastic Compute Cloud (Amazon EC2) instance types:
When an io2 volume is attached to any of the preceding Amazon EC2 instance types, it automatically becomes an io2 Block Express volume.
The price for Amazon EBS volume types is determined by storage and IOPS. The price for storage between the volume types is the same. However, the price for IOPS varies depending on the number of IOPS that are provisioned. For more information see Amazon EBS pricing, and choose the AWS Region that you're in from the Region dropdown menu.