💾Block Storage

NEW

A storage architecture that exposes fixed-size blocks to hosts for low-latency filesystems and databases.

DESCRIPTION

Block storage presents raw volumes as fixed-size blocks that a host OS formats with a filesystem or uses directly for databases. It is typically delivered via local buses, iSCSI, Fibre Channel, or cloud services like Amazon EBS. Block storage offers low latency, high IOPS, and fine-grained performance control, making it ideal for transactional workloads. Unlike object storage, it lacks built-in metadata and HTTP access, but supports snapshots and replication at the volume level. Common use cases include VM disks, database volumes, and high-performance applications.

ALTERNATIVE DEFINITIONS

AWS

Block storage is a data storage format that stores data in fixed-sized blocks.

Concise definition emphasizing block granularity.

Source

IBM

Block storage is a type of data storage where data is stored in fixed-size blocks and controlled by a server-based operating system.

Highlights host control and OS-level management of volumes.

Source

Wikipedia

Block-level storage is a technology that stores data in fixed-sized chunks called blocks.

General encyclopedic phrasing focusing on block-level abstraction.

Source

RELATED TERMS

Network Attached Storage Direct Attached Storage Amazon EBS Persistent Volume iSCSI Fibre Channel NVMe File System

COMPETING TERMS

Object Storage File Storage

KNOWLEDGE AREAS

Infrastructure Data Storage & Operations Cloud

TARGET AUDIENCE

Cloud Architect DevOps Engineer Software Architect IT Manager Hardware Engineer

EXTERNAL SOURCES

• Wikipedia - Block-level storage
• Amazon EBS - Managed block storage for EC2
• Microsoft Azure - Azure managed disk types overview
• Google Cloud - Persistent disks for Compute Engine

TOP QUESTIONS

When should I use block storage?

Use block storage for low-latency workloads like databases, virtual machine disks, and transactional applications requiring consistent IOPS and throughput.

Category: Usage

How does block storage differ from object storage?

Block storage exposes raw volumes managed by the OS, while object storage offers HTTP-accessible objects with metadata and built-in scalability.

Category: Comparison

What protocols deliver block storage?

Common protocols include iSCSI, Fibre Channel, NVMe over Fabrics, and cloud-managed services like Amazon EBS.

Category: Technology

What are typical performance metrics for block storage?

IOPS, throughput (MB/s), and latency are key. Volume size, disk type, and queue depth affect these metrics.

Category: Performance

How do snapshots work on block storage?

Snapshots capture point-in-time states of a volume, enabling backups, cloning, or rapid recovery with minimal downtime.

Category: Operations

What is a common pitfall with block storage?

Underprovisioning IOPS or not aligning filesystem settings to workload patterns can cause performance bottlenecks.

Category: Mistakes

Is block storage suitable for big data analytics?

Often object storage is preferred for large-scale analytics, while block storage is suited for hot data and compute-attached processing.

Category: BestPractices

How is block storage secured?

Use encryption at rest, in-transit encryption (e.g., IPsec), IAM controls, and snapshot access governance.

Category: Security

Can block storage be shared across multiple hosts?

Yes, via clustered filesystems or shared protocols, but careful coordination is required to avoid data corruption.

Category: Architecture