> ## Documentation Index
> Fetch the complete documentation index at: https://docs.xloud.tech/llms.txt
> Use this file to discover all available pages before exploring further.

# Volume Types and Storage Tiers

> Understand Xloud Block Storage volume types, storage performance tiers, and how to select the right tier for your workload requirements.

## Overview

A <Tooltip tip="A named storage profile that maps to a specific backend, performance tier, and optional encryption policy">volume type</Tooltip> is the mechanism through which administrators expose storage tiers to users. Each type maps to a backend driver and optionally enforces I/O quality-of-service limits. When creating a volume, selecting the appropriate type ensures the data lands on the correct hardware and receives the expected performance characteristics.

<Note>
  **Prerequisites**

  * Volume types are defined by your administrator
  * Contact your administrator if the required type is not available in your project
</Note>

***

## Storage Tiers

Xloud Block Storage supports tiered storage configurations. Each tier corresponds to a
hardware class with distinct performance characteristics:

| Tier         | Hardware          | IOPS (4K Random)    | Throughput        | Best For                                                             |
| ------------ | ----------------- | ------------------- | ----------------- | -------------------------------------------------------------------- |
| **NVMe**     | PCIe NVMe SSDs    | 100,000 – 1,000,000 | 3 – 14 GB/s       | Transactional databases, low-latency caches, real-time analytics     |
| **SSD**      | SATA/SAS SSDs     | 10,000 – 100,000    | 500 MB/s – 2 GB/s | Web application data, instance boot disks, general-purpose workloads |
| **Standard** | 7.2K/10K RPM HDDs | 150 – 500           | 100 – 300 MB/s    | Archival storage, bulk data, infrequent access                       |

<Tip>
  Select the tier based on your workload's I/O profile — not just raw capacity.
  Placing a high-transaction database on a Standard (HDD) type will result in
  significant latency and throughput bottlenecks. Use NVMe for latency-sensitive
  workloads and SSD for most application data.
</Tip>

***

## View Available Volume Types

<Tabs>
  <Tab title="Dashboard" icon="gauge">
    Volume types are visible when creating a volume. Navigate to **Storage > Volumes**
    and click **Create Volume**. The **Volume Type** selection table in the create form
    shows all types available to your project with their properties.

    <Note>
      There is no standalone Volume Types listing page for regular users. Volume types
      are managed by administrators through the admin view at **Storage > Volume Types**.
    </Note>
  </Tab>

  <Tab title="CLI" icon="terminal">
    <Steps titleSize="h3">
      <Step title="Authenticate" icon="key">
        Source your credentials file to authenticate with the Xloud platform:

        ```bash title="Load credentials" theme={null}
        source openrc.sh
        ```

        <Tip>
          Your administrator provides the RC (credentials) file for your project. See [CLI Setup](/cli-setup) for configuration details.
        </Tip>
      </Step>

      <Step title="List volume types" icon="list">
        ```bash title="List all available volume types" theme={null}
        openstack volume type list --long
        ```

        ```bash title="Show details and extra specs for a type" theme={null}
        openstack volume type show <type-name>
        ```

        The `extra_specs` field shows backend-specific properties such as:

        * `volume_backend_name` — routes volumes to the correct backend
        * `capabilities:replication_enabled` — whether replication is enabled
        * `qos` — associated QoS spec name
      </Step>
    </Steps>
  </Tab>
</Tabs>

***

## Select a Volume Type for Your Workload

<AccordionGroup>
  <Accordion title="Databases (MySQL, PostgreSQL, MongoDB)" icon="database">
    **Recommended tier**: NVMe or SSD

    Databases require consistent low-latency random I/O. NVMe is the preferred choice
    for production databases with high transaction rates. SSD provides an acceptable
    balance for development and staging environments.

    | Database                     | Recommended Type | Rationale                                     |
    | ---------------------------- | ---------------- | --------------------------------------------- |
    | MySQL / MariaDB (production) | `nvme`           | High write IOPS for WAL and data pages        |
    | PostgreSQL (production)      | `nvme`           | Random read/write for shared\_buffers and WAL |
    | MongoDB                      | `ssd`            | Mixed read/write, benefits from SSD caching   |
    | Development / staging        | `ssd`            | Cost-effective for lower traffic              |
  </Accordion>

  <Accordion title="Web and Application Servers" icon="server">
    **Recommended tier**: SSD

    Web application data — configuration, assets, application state — requires moderate
    IOPS with good throughput. SSD types deliver an optimal balance of performance and
    cost for these workloads.
  </Accordion>

  <Accordion title="Archival and Bulk Storage" icon="archive">
    **Recommended tier**: Standard (HDD)

    Log archives, data warehouses, and infrequently accessed bulk storage do not
    require high IOPS. Standard HDD-backed volumes provide large capacity at lower
    cost per GiB.
  </Accordion>

  <Accordion title="Boot Disks (Instance Root Volumes)" icon="hard-drive">
    **Recommended tier**: SSD

    Instance boot volumes are read-intensively at startup and write-intensively during OS
    operations. SSD provides the performance needed for fast boot times and responsive
    OS operations.
  </Accordion>
</AccordionGroup>

***

## Encryption-Enabled Types

Some volume types have encryption configured by your administrator. Volumes created
from an encrypted type are automatically encrypted at creation — no additional action
is required from you.

<Note>
  Encrypted volume types require the Xloud Key Management service to be accessible.
  If encryption is required for compliance, confirm with your administrator that an
  encrypted type is available and that key management is configured for your environment.
</Note>

```bash title="Check if a volume type has encryption configured" theme={null}
openstack volume type show <type-name> -c encryption
```

***

## Next Steps

<CardGroup cols={2}>
  <Card title="Create a Volume" href="/services/storage/create-volume" color="#197560">
    Create a volume using the appropriate type for your workload
  </Card>

  <Card title="Volume Types Admin" href="/services/storage/volume-types-admin" color="#197560">
    Administrators: create types, set backend associations, and configure QoS
  </Card>

  <Card title="Storage Tiers (Admin)" href="/services/storage/storage-tiers" color="#197560">
    Configure NVMe, SSD, and HDD tier mappings for your storage cluster
  </Card>

  <Card title="Encryption (Admin)" href="/services/storage/encryption" color="#197560">
    Enable at-rest encryption on volume types using the key management service
  </Card>
</CardGroup>