Storage in AWS
Persistent Block Storage
Amazon Elastic Block Store (EBS) provides block-level storage volumes for EC2 instances. Block storage divides data into fixed-size blocks, and the operating system recognizes attached EBS volumes as local disks. You can install applications, store databases, and write files as you would on a physical server.
EBS volumes are persistent, data remains intact if an EC2 instance is stopped or terminated. This distinguishes EBS from ephemeral instance storage, which is lost on termination. EBS offers different volume types optimized for workloads ranging from general-purpose use to high IOPS required by databases.
Performance is predictable and configurable. Because EBS volumes are network-attached within the same Availability Zone, they provide durability without being physically tied to a single machine. The tradeoff is that volumes are limited to a specific AZ, requiring snapshots or replication for cross-zone redundancy.
EBS snapshots provide incremental backups stored in Amazon S3. They enable recovery from data corruption and allow volumes to be recreated in other Availability Zones or Regions, enhancing resilience and disaster recovery.
Simple Object Storage
Amazon Simple Storage Service (S3) provides object storage at massive scale. Instead of attaching storage as a disk, you store objects inside globally unique containers called buckets. Each object consists of data, metadata, and a unique identifier, accessed via API calls rather than file system mounts.
S3 is designed for unstructured data such as images, videos, backups, logs, and static website assets. There is no practical limit to the number of objects or total storage capacity. Objects reside within a specific Region unless replication is configured.
Why is S3 considered the most durable AWS service? Amazon S3 is designed for 99.999999999% durability (“11 nines”). It achieves this by automatically storing multiple copies of each object across multiple devices and Availability Zones within a Region. If a device fails, redundant copies preserve the data automatically and transparently. This level of durability makes S3 suitable for critical backups, archival storage, and data lakes.
Block Storage vs Object Storage
EBS and S3 serve fundamentally different purposes:
- EBS provides low-latency, high-performance block storage attached to EC2 instances. It supports file systems and databases requiring direct disk access.
- S3 provides scalable object storage accessed through APIs. It is ideal for storing large volumes of unstructured data and static content.
Applications requiring a mounted disk use EBS. Applications distributing static assets or storing backups use S3. EBS is typically more expensive per gigabyte because it delivers lower latency and higher performance. S3 provides lower-cost storage at a massive scale with high durability.
Integrated Compute and Storage Strategy
In many architectures, EC2 and EBS operate together for application execution and transactional workloads, while S3 serves as durable storage for backups, static assets, and data archives. For example, a web application might run on EC2, store transactional database data on EBS, and store user-uploaded images in S3. This layered approach separates performance-sensitive storage from scalable object storage, ensuring both performance efficiency and cost control.
My name is Naeem ul Haq. I’ve been working with AWS since its early days and have deep expertise across its evolving ecosystem.
