Amazon EBS provides two major categories of storage:
1. SSD-backed storage that is used for transactional workloads
2. HDD-backed storage that is used for achieving throughput for your workloads.
SSD-backed volumes are designed in such a way that it works for transactional and workloads that require high IOPS. HDD-backed volumes are designed for achieving throughput-intensive and the big-data workloads.
Hope you got the answer.