Amazon EBS
A block storage service that attaches to EC2 instances, offering multiple volume types including SSD and HDD to match different workload requirements
Overview
Amazon Elastic Block Store (EBS) is a high-performance block storage service used with EC2 instances. It serves as storage for file systems and databases, and data persists even when instances are stopped or restarted. Four volume types are available: General Purpose SSD (gp3), Provisioned IOPS SSD (io2), Throughput Optimized HDD (st1), and Cold HDD (sc1), allowing you to choose based on the balance of IOPS performance, throughput, and cost. EBS volumes are automatically replicated within the same Availability Zone, protecting data from single hardware failures. The snapshot feature lets you save point-in-time backups of volumes to S3 and restore them in a different Availability Zone or region.
gp3 and io2 - Volume Selection Based on IOPS Requirements
The four EBS volume types are selected based on workload characteristics. gp3 (General Purpose SSD) is the most versatile, including a baseline of 3,000 IOPS and 125 MB/s throughput, with the option to independently scale up to 16,000 IOPS for an additional fee. It suits the majority of workloads and offers excellent cost-performance. Unlike Azure Managed Disks Standard SSD, which does not allow independent IOPS and throughput configuration, gp3 gives you granular control over both parameters. io2 Block Express (Provisioned IOPS SSD) delivers up to 256,000 IOPS - exceeding Azure Ultra Disk's 160,000 IOPS ceiling - and is designed for large-scale databases (Oracle, SAP HANA, etc.) and latency-sensitive transaction processing. st1 (Throughput Optimized HDD) targets workloads with primarily sequential access, such as big data processing and log analysis. sc1 (Cold HDD) is best for infrequently accessed data storage and has the lowest per-GB monthly cost.
Snapshot and Encryption Design
EBS snapshots use an incremental backup approach that stores only changed blocks, minimizing both storage costs and creation time. You can restore snapshots in a different Availability Zone or region, making them a core building block for disaster recovery strategies. Scheduling regular snapshots through Amazon Data Lifecycle Manager automates backup retention and cleanup without manual intervention. EBS encryption should be enabled by default, using KMS customer-managed keys so that key rotation and access control can be managed according to organizational policies. Enabling default encryption at the account level ensures that every new volume is automatically encrypted, eliminating the risk of unencrypted volumes being created by oversight. For a deeper look at Amazon EBS, related books on Amazon are also available.
Cost Optimization and Sizing Considerations
EBS cost optimization starts with right-sizing volumes. Migrating from gp2 to gp3 can achieve up to 20% cost savings while maintaining equivalent or better performance, since gp3 decouples IOPS and throughput from volume size. Monitoring actual IOPS and throughput utilization through CloudWatch metrics helps identify over-provisioned volumes that can be downsized. For io2 volumes, provisioning only the IOPS actually needed rather than peak theoretical demand significantly reduces monthly costs. Transitioning infrequently accessed snapshots to the EBS Snapshots Archive tier cuts snapshot storage costs by up to 75%. When designing volume sizes, account for growth headroom but avoid excessive over-provisioning - EBS Elastic Volumes lets you resize, change type, and adjust performance of live volumes without downtime, so you can start conservatively and scale up as needed.