---
title: "Product Description Network Volumes for Dedicated Servers"
sidebar_label: "Overview"
sidebar_position: 1
description: "What types of network volumes are available, what network volume limits exist, and the cost of network volumes"
---

import Formbricks from '@theme/MDXComponents/Formbricks';
import { CustomTable } from '@selectel/docux/components';
import BlockStoragePools from '@site/i18n/en/docusaurus-plugin-content-docs/current/_partials/dedicated/block-storage/block-storage-pools.mdx';

# Product Description Network Volumes for Dedicated Servers

A network volume for dedicated servers is a scalable external network block storage with triple data replication. Triple replication of disk volumes ensures high data integrity. Suitable for rapid scaling of server disk space.

<BlockStoragePools />

## How it works \{#principle-of-operation}

A network volume can be connected to one or more dedicated servers. Connection is performed via the iSCSI protocol.

All servers and network volumes are combined into a single group when they are connected in the Control Panel — for more information, see the [Connect a network volume to a server](/block-storage/manage/connect-block-storage-to-linux.mdx#connect-block-storage-to-server-in-panel) subsection of the Connect a network volume to a server instructions. A network volume can be connected only to the entire group at once — it will be available to all servers in the group.

### Example of links between network volumes and dedicated servers in a group \{#server-and-block-storage-group}

![](https://423.selcdn.ru/kb/dedic-about-block-storage-server-and-block-storage-group-LANG-THEME.png)

### Example of combining dedicated servers and network volumes into a single group \{#connecting-dedicated-servers-and-block-storage-into-single-group}

![](https://423.selcdn.ru/kb/dedic-about-block-storage-connecting-dedicated-servers-and-block-storage-into-single-group-LANG-THEME.png)

## Types of network volumes \{#block-storage-types}

Selectel provides two types of network volumes:

* Basic HDD – an HDD based on enterprise-class SATA drives. Suitable for storing large volumes of data that do not require frequent reading or overwriting;
* Fast SSD – an NVMe SSD with fast response and high performance. Suitable for operations requiring high read and write speeds.

Disk types differ in minimum and maximum size limits, throughput values, and the number of read and write operations. For more information, see the [Network volume limits](#block-storage-limits) table.

## Limits and restrictions \{#limits-and-restrictions}

Only one SAN network is available in each region.

By default, only three network volumes can be created per account. The number of network volumes and the maximum disk size can be increased; to do this, [create a ticket](https://my.selectel.ru/tickets/create).

### Network volume limits \{#block-storage-limits}

<CustomTable>
  <table data-sticky>
    <thead>
      <tr>
        <th />

        <th>Basic HDD</th><th>Fast SSD</th>
      </tr>
    </thead>

    <tbody>
      <tr>
        <th>Minimum size</th><td>100 GB</td><td>100 GB</td>
      </tr>

      <tr>
        <th>Maximum size</th><td>5 TB</td><td>5 TB</td>
      </tr>

      <tr>
        <th>Throughput</th><td>100 MB/s</td><td>500 MB/s</td>
      </tr>

      <tr>
        <th>Read operations</th><td>320 IOPS</td><td>25000 IOPS</td>
      </tr>

      <tr>
        <th>Write operations</th><td>120 IOPS</td><td>15000 IOPS</td>
      </tr>
    </tbody>
  </table>
</CustomTable>

<Formbricks />