EBS Volume Types

General Purpose SSD (gp3, and the older gp2) is the default, balanced choice for most workloads — boot volumes, small-to-medium databases, dev/test environments. gp3 specifically lets you provision IOPS and throughput independently of storage size (a meaningful improvement over gp2, where performance scaled with size), so you can size for capacity and performance separately and pay only for what you actually need.

Provisioned IOPS SSD (io1/io2) is designed for the most demanding, latency-sensitive, high-IOPS workloads — large production databases needing consistent sub-millisecond latency at high transaction rates. io2 Block Express extends this further for the very largest, most demanding database workloads. This is also the volume type family that supports EBS Multi-Attach, letting a volume be attached to multiple instances simultaneously (only with a cluster-aware file system that manages concurrent access correctly).

Throughput Optimized HDD (st1) and Cold HDD (sc1) are magnetic-disk-backed, lower-cost options for large, sequential-access workloads like big data processing or infrequently accessed data — they're cheaper per GB but have much lower IOPS ceilings and are unsuitable for random-access or boot volume use.