Block Storage

Definition

Block storage is a data storage architecture that splits data into fixed-size blocks, each addressed independently, and presents the result to a server as a raw, unformatted volume — much like a physical hard disk.

Overview

Block storage is one of the three main cloud storage models, alongside object and file storage. Instead of storing data as whole files with metadata, it breaks data into equal-sized blocks and gives each one a unique address, leaving the operating system free to organize those blocks with whatever filesystem it chooses (ext4, NTFS, XFS, and so on). Because the OS talks to a block volume the same way it talks to a local disk, block storage delivers low, predictable latency and high IOPS, which makes it the default choice for boot volumes on VPS Hosting and Dedicated Server Hosting, as well as for databases and other transactional workloads that need consistent random read/write performance. Most cloud providers let a block volume attach to only one compute instance at a time, and support live resizing, snapshotting, and cloning for backup and Disaster Recovery purposes. Block storage contrasts with object storage — used for unstructured data like backups, media, and static assets and accessed over HTTP APIs rather than a filesystem — and with file storage, which is shared across multiple machines via protocols like NFS or SMB. Understanding this distinction is a core part of AWS Core Services and similar cloud fundamentals training, since choosing the wrong storage type for a workload is a common architecture mistake.

Key Concepts

• Data divided into fixed-size, independently addressable blocks
• Presented to the OS as a raw volume formattable with any filesystem
• Low, predictable latency suited to random read/write access
• Typically attaches to a single compute instance at a time
• Supports live resizing, snapshots, and cloning
• Underpins RAID-style redundancy configurations

Use Cases

Frequently Asked Questions

Related in Cloud