Why can't I use the new st1/sc1 EBS volumes by AWS as root volumes

Question

AWS launched sc1 and st1 HDD EBS volume types recently, I can't seem to use these as root volumes while launching new EC2 instances or launching from already created AMI's (tried both).

I chose an m4 machine, in any case, the root volume is EBS itself, below is a screenshot, the second volume that I add gets the new options, however the first one I can't choose the same. Is this by design AWS people?

Answer 1

If you look from http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSVolumeTypes.html

under the main table for volume type as Throughput Optimized HDD (st1) and Cold HDD (sc1) it says

Cannot be a boot volume

and below

Throughput Optimized HDD (st1) volumes provide low-cost magnetic storage that defines performance in terms of throughput rather than IOPS. This volume type is a good fit for large, sequential workloads such as Amazon EMR, ETL, data warehouses, and log processing. Bootable st1 volumes are not supported.

and

Cold HDD (sc1) volumes provide low-cost magnetic storage that defines performance in terms of throughput rather than IOPS. With a lower throughput limit than st1, sc1 is a good fit ideal for large, sequential cold-data workloads. If you require infrequent access to your data and are looking to save costs, sc1 provides inexpensive block storage. Bootable sc1 volumes are not supported.