---
title: "Disks in a ClickHouse® cluster"
sidebar_label: "Disks"
description: "Key information about the disks used in a ClickHouse® database cluster"
sidebar_position: 3
---

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# Disks in a ClickHouse® cluster

In a ClickHouse® managed database cluster, you can use [local](#local-disks) and [network volumes](#network-volumes). The disk type used depends on the [configuration line selected](/managed-databases/clickhouse/configurations.mdx#configuration-lines).

You can select a configuration line with the required disk type and disk size when [creating a managed database cluster](/managed-databases/clickhouse/create-cluster.mdx). After the cluster is created, you can change the line to another one with the same disk type and increase the disk size — [scale the cluster](/managed-databases/clickhouse/resize-cluster.mdx).

Disk performance and bandwidth for different configuration lines can be viewed in the [Performance and Bandwidth](#performance-and-bandwidth) table.

## Local disks \{#local-disks}

<CustomTable>
  <table>
    <tbody>
      <tr>
        <th>Configuration lines</th>

        <td>
          <ul>
            <li>Standard;</li><li>CPU;</li><li>Memory;</li><li>HighFreq;</li><li>Flex</li>
          </ul>
        </td>
      </tr>

      <tr>
        <th>Volume type</th><td>SSD NVMe volume</td>
      </tr>

      <tr>
        <th>Technical details</th><td>The disk subsystem is configured in RAID 10 for Standard, CPU, Memory, HighFreq, and Flex lines</td>
      </tr>

      <tr>
        <th>Advantages</th><td>Low data access latency</td>
      </tr>

      <tr>
        <th>Usage</th><td>Suitable for tasks sensitive to read/write speed metrics</td>
      </tr>

      <tr>
        <th>Number of volumes in DBMS</th><td>1</td>
      </tr>

      <tr>
        <th>Changing configuration</th>

        <td>
          <ul>
            <li>in all configuration lines with a local disk, except Flex, you cannot increase the local disk alone; you can change the entire node configuration — [scale the cluster](/managed-databases/clickhouse/resize-cluster.mdx)</li>
          </ul>
        </td>
      </tr>

      <tr>
        <th>Detaching volume</th><td>✗</td>
      </tr>

      <tr>
        <th>Connect to another database</th><td>✗</td>
      </tr>

      <tr>
        <th>Create another volume, snapshot, or backup</th><td>✗</td>
      </tr>

      <tr>
        <th>Deletion</th><td>Deleted along with all data when the cluster is deleted</td>
      </tr>
    </tbody>
  </table>
</CustomTable>

## Network volumes \{#network-volumes}

<CustomTable>
  <table>
    <tbody>
      <tr>
        <th>Configuration lines</th><td>Flex</td>
      </tr>

      <tr>
        <th>Volume type</th><td>SSD NVMe volume</td>
      </tr>

      <tr>
        <th>Technical details</th><td>Managed by a Software-Defined Storage (SDS) system — Ceph</td>
      </tr>

      <tr>
        <th>Advantages</th>

        <td>
          <ul>
            <li>triple volume replication;</li><li>network volume size is independent of the number of vCPUs</li>
          </ul>
        </td>
      </tr>

      <tr>
        <th>Usage</th><td>Not recommended for systems sensitive to network latency and response time (latency). For example, it is suitable for archival data storage</td>
      </tr>

      <tr>
        <th>Number of volumes in DBMS</th><td>1</td>
      </tr>

      <tr>
        <th>Changing configuration</th>

        <td>
          <ul>
            <li>there is no downtime when changing the volume size;</li><li>when changing the number of vCPUs and RAM, downtime depends on the number of nodes in the cluster: in single-node clusters, downtime is equal to the node reboot time (one to two minutes), and in multi-node clusters, it is equal to the time taken to switch to another node (less than one minute)</li>
          </ul>
        </td>
      </tr>

      <tr>
        <th>Detaching volume</th><td>✗</td>
      </tr>

      <tr>
        <th>Connect to another database</th><td>✗</td>
      </tr>

      <tr>
        <th>Create another volume, snapshot, or backup</th><td>✗</td>
      </tr>

      <tr>
        <th>Deletion</th><td>Deleted along with all data when the cluster is deleted</td>
      </tr>
    </tbody>
  </table>
</CustomTable>

## Performance and bandwidth \{#performance-and-bandwidth}

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      Standard
    </TabItemLabel>

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        <thead>
          <tr>
            <th />

            <th>Volumes<br /> up to 256 GB</th><th>Volumes<br /> 512 GB</th><th>Volumes<br /> 768 GB</th><th>Volumes<br /> 1 TB</th><th>Volumes<br /> 1.5 TB</th><th>Volumes<br /> 2 TB</th><th>Volumes<br /> 2.5 TB</th>
          </tr>
        </thead>

        <tbody>
          <tr>
            <th>Bandwidth</th><td>400 MB/s</td><td>500 MB/s</td><td>600 MB/s</td><td>700 MB/s</td><td>800 MB/s</td><td>900 MB/s</td><td>1 000 MB/s</td>
          </tr>

          <tr>
            <th>Performance (read)</th><td>25 600 IOPS</td><td>40 000 IOPS</td><td>50 000 IOPS</td><td>60 000 IOPS</td><td>70 000 IOPS</td><td>80 000 IOPS</td><td>90 000 IOPS</td>
          </tr>

          <tr>
            <th>Performance (write)</th><td>12 800 IOPS</td><td>20 000 IOPS</td><td>25 000 IOPS</td><td>30 000 IOPS</td><td>35 000 IOPS</td><td>40 000 IOPS</td><td>45 000 IOPS</td>
          </tr>
        </tbody>
      </table>
    </CustomTable>
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  <TabItem value="cpu">
    <TabItemLabel>
      CPU
    </TabItemLabel>

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

            <th>Volumes<br /> up to 256 GB</th><th>Volumes<br /> 512 GB</th><th>Volumes<br /> 768 GB</th><th>Volumes<br /> 1 TB</th><th>Volumes<br /> 1.5 TB</th><th>Volumes<br /> 2 TB</th><th>Volumes<br /> 2.5 TB</th>
          </tr>
        </thead>

        <tbody>
          <tr>
            <th>Bandwidth</th><td>400 MB/s</td><td>500 MB/s</td><td>600 MB/s</td><td>700 MB/s</td><td>800 MB/s</td><td>900 MB/s</td><td>1 000 MB/s</td>
          </tr>

          <tr>
            <th>Performance (read)</th><td>25 600 IOPS</td><td>40 000 IOPS</td><td>50 000 IOPS</td><td>60 000 IOPS</td><td>70 000 IOPS</td><td>80 000 IOPS</td><td>90 000 IOPS</td>
          </tr>

          <tr>
            <th>Performance (write)</th><td>12 800 IOPS</td><td>20 000 IOPS</td><td>25 000 IOPS</td><td>30 000 IOPS</td><td>35 000 IOPS</td><td>40 000 IOPS</td><td>45 000 IOPS</td>
          </tr>
        </tbody>
      </table>
    </CustomTable>
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  <TabItem value="memory">
    <TabItemLabel>
      Memory
    </TabItemLabel>

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

            <th>Volumes<br /> up to 256 GB</th><th>Volumes<br /> 512 GB</th><th>Volumes<br /> 768 GB</th><th>Volumes<br /> 1 TB</th><th>Volumes<br /> 1.5 TB</th><th>Volumes<br /> 2 TB</th><th>Volumes<br /> 2.5 TB</th>
          </tr>
        </thead>

        <tbody>
          <tr>
            <th>Bandwidth</th><td>400 MB/s</td><td>500 MB/s</td><td>600 MB/s</td><td>700 MB/s</td><td>800 MB/s</td><td>900 MB/s</td><td>1 000 MB/s</td>
          </tr>

          <tr>
            <th>Performance (read)</th><td>25 600 IOPS</td><td>40 000 IOPS</td><td>50 000 IOPS</td><td>60 000 IOPS</td><td>70 000 IOPS</td><td>80 000 IOPS</td><td>90 000 IOPS</td>
          </tr>

          <tr>
            <th>Performance (write)</th><td>12 800 IOPS</td><td>20 000 IOPS</td><td>25 000 IOPS</td><td>30 000 IOPS</td><td>35 000 IOPS</td><td>40 000 IOPS</td><td>45 000 IOPS</td>
          </tr>
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  <TabItem value="highfreq">
    <TabItemLabel>
      HighFreq
    </TabItemLabel>

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

            <th>Volumes<br /> 64 GB</th><th>Volumes<br /> 128 GB</th><th>Volumes<br /> 256 GB</th><th>Volumes<br /> 512 GB</th><th>Volumes<br /> 768 GB</th><th>Volumes<br /> 962 GB</th><th>Volumes<br /> 1.22 TB</th><th>Volumes<br /> 1.5 TB</th><th>Volumes<br /> 2 TB</th>
          </tr>
        </thead>

        <tbody>
          <tr>
            <th>Bandwidth</th><td>400 MB/s</td><td>500 MB/s</td><td>600 MB/s</td><td>700 MB/s</td><td>800 MB/s</td><td>900 MB/s</td><td>1 000 MB/s</td><td>1 100 MB/s</td><td>1 200 MB/s</td>
          </tr>

          <tr>
            <th>Performance (read)</th><td>25 600 IOPS</td><td>40 000 IOPS</td><td>50 000 IOPS</td><td>60 000 IOPS</td><td>70 000 IOPS</td><td>80 000 IOPS</td><td>90 000 IOPS</td><td>100 000 IOPS</td><td>120 000 IOPS</td>
          </tr>

          <tr>
            <th>Performance (write)</th><td>12 800 IOPS</td><td>20 000 IOPS</td><td>25 000 IOPS</td><td>30 000 IOPS</td><td>35 000 IOPS</td><td>40 000 IOPS</td><td>45 000 IOPS</td><td>50 000 IOPS</td><td>60 000 IOPS</td>
          </tr>
        </tbody>
      </table>
    </CustomTable>
  </TabItem>

  <TabItem value="flex">
    <TabItemLabel>
      Flex
    </TabItemLabel>

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

            <th>Local disk</th><th>Network volume</th>
          </tr>
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        <tbody>
          <tr>
            <th>Bandwidth</th><td>300 MB/s</td><td>500 MB/s</td>
          </tr>

          <tr>
            <th>Performance (read)</th><td>12 800 IOPS</td><td>25 000 IOPS</td>
          </tr>

          <tr>
            <th>Performance (write)</th><td>6 400 IOPS</td><td>15 000 IOPS</td>
          </tr>
        </tbody>
      </table>
    </CustomTable>
  </TabItem>
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