Amazon Elastic Block Store

EBS

You need a high-performance, persistent block storage volume to mount as a local hard drive on a single virtual server.

Reach for it when

Providing boot volumes and root file systems for EC2 virtual machine instances.
Hosting database files for self-managed databases like PostgreSQL or MongoDB on EC2.
Running transactional applications that require sub-millisecond latencies for disk writes.

Sharing files simultaneously across hundreds of separate virtual machine instances — use EFS or S3 instead.
Storing static media assets that are accessed globally by users via web browsers — use S3 instead.
Creating a temporary scratch disk for ephemeral data that does not need to persist after shutdown — use Instance Store instead.

Service	Pick it instead when
EFS	Choose it when you need a shared network file system that multiple EC2 instances can read and write to concurrently.
S3	Choose it when storing unstructured objects that do not need to be mounted as a file system.

The model: Pay per GB provisioned per month, plus fees for provisioned IOPS on gp3/io2 volumes.
The line item that surprises people: You are billed for the full provisioned capacity of the volume regardless of whether the OS has written any data.

Most EBS volumes can only be attached to one EC2 instance at a time within the exact same Availability Zone.
Changing volume size or performance settings is rate-limited to once every six hours per volume.
The max IOPS of gp3 volumes is capped at 3000 unless you pay an extra monthly fee to provision more.

This page is a concept reference. Cost models are qualitative; confirm the current offering, Region and pricing before deploying.