---
title: Block Storage - Concepts
description: Explore essential concepts of Block Storage, including block devices, IOPS, SANs, local volumes, and their roles in enhancing storage performance and reliability.
tags: block storage volumes concept
dates:
  validation: 2025-06-09
  posted: 2023-11-23
---
import AvailabilityZone from '@macros/concepts/availability-zone.mdx'
import BlockSnapshot from '@macros/concepts/block-snapshot.mdx'
import BlockVolumes from '@macros/concepts/block-volumes.mdx'
import LocalVolumes from '@macros/concepts/local-volumes.mdx'
import Region from '@macros/concepts/region.mdx'
import StorageBootOnBlock from '@macros/storage/boot-on-block.mdx'


## Availability Zone

<AvailabilityZone />

## Block volumes

<BlockVolumes />

## Boot-on-block

<StorageBootOnBlock />

## IOPS

IOPS or Input/Ouptut Operations Per Second, is a unit of measurement that indicates how many read/write operations a storage device is performing per second.

Scaleway Block Storage offers two IOPS limits:

- 5000 IOPS (5K IOPS)
- 15 000 IOPS (15K IOPS)

Refer to the [dedicated documentation](/block-storage/reference-content/differences-between-5kiops-volumes/) for more information on the IOPS of each Block Storage volume type.

## Local volume

<LocalVolumes />

## Region

<Region />

## Snapshot

<BlockSnapshot />

## Storage Area Networks (SANs)

A Storage Area Network (SAN) consists of interconnected machines, network infrastructure and storage devices designed for performance and high-availability. Unlike a Network Attached Storage (NAS) which stores all data on a [file level](https://www.scaleway.com/en/blog/understanding-the-different-types-of-storage/#what-is-file-storage), the SAN stores all data on [block level](https://www.scaleway.com/en/blog/understanding-the-different-types-of-storage/#what-is-block-storage), this makes SAN a perfect solution for business critical applications and input/output intense operations like relational databases. The SAN is a network-connected solution, that operates independently from the local hypervisor hosting the virtual Instance. The storage capacity of the block devices on the SAN can be tailored towards your requirements.

## Volumes

A volume is a storage space used by your Instances. Several volumes can be [attached to an Instance](/block-storage/how-to/attach-a-volume/). In addition, they can be [snapshotted](/block-storage/how-to/create-a-snapshot/), [mounted](/block-storage/how-to/mount-a-volume/), or [unmounted](/block-storage/how-to/unmount-a-volume/).