Storage
Amazon EBS
Block storage volumes for EC2
Amazon EBS provides persistent block-level volumes attached to EC2 instances in a single AZ. Families: gp3 (general SSD), io2/io2 Block Express (provisioned IOPS), st1 (throughput HDD), sc1 (cold HDD). Snapshots stored in S3 enable backup and cross-AZ/Region copies.
When to use it
- Boot volumes and databases needing low-latency block storage
- io2 when a database needs high sustained IOPS
- Workloads where data must persist independent of instance lifecycle
When NOT to use it
- Shared access from many instances across AZs (use EFS)
- Object-style access over HTTP (use S3)
- Temporary scratch data where instance store is cheaper
Key exam points
- Volumes live in one AZ; snapshots go to S3 and can recreate volumes in other AZs/Regions
- io2 provides provisioned IOPS for latency-sensitive databases
- Encryption is supported at rest and in transit to the instance
- Volumes persist after instance termination when delete-on-termination is disabled
Compared with
- Amazon EFS — EBS attaches to a single instance in one AZ; EFS is shared across AZs.
- Amazon S3 — S3 is object storage for durability/scale; EBS is block storage for a running workload.