> ## 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 QoS (Admin)

> Create and manage Xloud Block Storage volume types, set backend associations via extra specs, and configure QoS policies to enforce I/O limits per storage tier.

## Overview

Volume types are the mechanism through which administrators expose storage tiers to users. Each volume type maps to a specific backend through the `volume_backend_name` extra spec and optionally enforces I/O quality-of-service limits. Well-defined volume types are essential for predictable workload performance and efficient backend utilization.

<Warning>
  **Administrator Access Required** — This operation requires the `admin` role. Contact your
  Xloud administrator if you do not have sufficient permissions.
</Warning>

<Note>
  **Prerequisites**

  * Administrator credentials with the `admin` role
  * At least one storage backend configured and registered with the scheduler
  * Backend names available via `openstack volume backend pool list --long`
</Note>

***

## Create a Volume Type

<Tabs>
  <Tab title="Dashboard" icon="gauge">
    <Steps titleSize="h3">
      <Step title="Navigate to Volume Types" icon="compass">
        Navigate to
        **Storage > Volume Types** (admin view).
      </Step>

      <Step title="Create the type" icon="plus">
        Click **Create Volume Type**. Enter a descriptive name (e.g., `nvme`, `ssd`,
        `standard`) and an optional description. Click **Confirm**.
      </Step>

      <Step title="Set the backend association" icon="link">
        In the volume type list, click the type name to open its details page. Under
        **Extra Specs**, click **Create** and add:

        | Key                   | Value            | Purpose                               |
        | --------------------- | ---------------- | ------------------------------------- |
        | `volume_backend_name` | `<backend-name>` | Routes volumes to the correct backend |

        <Tip>
          The value of `volume_backend_name` must exactly match the `volume_backend_name`
          configured in the backend driver settings. Use `openstack volume backend pool list`
          to confirm the correct name.
        </Tip>
      </Step>

      <Step title="Verify" icon="circle-check">
        Create a test volume using the new type and confirm it reaches `available` status:

        ```bash title="Test volume type" theme={null}
        openstack volume create --size 1 --type <type-name> test-vol
        openstack volume show test-vol -c status -c type
        openstack volume delete test-vol
        ```

        <Check>Volume type created and validated against the backend.</Check>
      </Step>
    </Steps>
  </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="Create the volume type" icon="plus">
        ```bash title="Create volume type" theme={null}
        openstack volume type create \
          --description "NVMe-backed high-performance storage" \
          nvme
        ```
      </Step>

      <Step title="Set the backend association" icon="link">
        ```bash title="Set extra spec for backend routing" theme={null}
        openstack volume type set \
          --property volume_backend_name=nvme-backend \
          nvme
        ```
      </Step>

      <Step title="Set as default (optional)" icon="star">
        ```bash title="Set default volume type" theme={null}
        openstack volume type set --default ssd
        ```

        The default type is used when users create volumes without specifying a type.
      </Step>

      <Step title="Verify" icon="circle-check">
        ```bash title="List volume types with properties" theme={null}
        openstack volume type list --long
        ```

        <Check>Volume type visible with correct backend association.</Check>
      </Step>
    </Steps>
  </Tab>
</Tabs>

***

## Configure QoS Policies

Quality-of-Service specs enforce I/O limits on volumes associated with a type. QoS
policies are applied at the hypervisor (`front-end`), at the storage backend (`back-end`),
or at both layers.

<Tabs>
  <Tab title="Dashboard" icon="gauge">
    <Steps titleSize="h3">
      <Step title="Create a QoS Spec" icon="gauge">
        Navigate to **Storage > Volume Types** (QoS Specs tab, admin view). Click **Create QoS Spec**.
        Enter a name (e.g., `ssd-standard-qos`) and set the consumer:

        | Consumer    | Effect                                                  |
        | ----------- | ------------------------------------------------------- |
        | `front-end` | Limits enforced at the hypervisor (recommended for RBD) |
        | `back-end`  | Limits enforced at the storage backend                  |
        | `both`      | Limits enforced at both layers                          |
      </Step>

      <Step title="Add I/O limit specs" icon="sliders">
        After creation, open the QoS Spec and add limits:

        | Key               | Example Value | Description                             |
        | ----------------- | ------------- | --------------------------------------- |
        | `total_iops_sec`  | `5000`        | Maximum combined read + write IOPS      |
        | `read_iops_sec`   | `3000`        | Read IOPS limit                         |
        | `write_iops_sec`  | `2000`        | Write IOPS limit                        |
        | `total_bytes_sec` | `524288000`   | Throughput cap in bytes/sec (500 MiB/s) |
        | `read_bytes_sec`  | `314572800`   | Read throughput cap (300 MiB/s)         |
        | `write_bytes_sec` | `209715200`   | Write throughput cap (200 MiB/s)        |
      </Step>

      <Step title="Associate with a volume type">
        Switch to the **Volume Types** tab. On the target volume type row, click
        **Manage QoS Spec** (the first row action). In the dialog, select the
        QoS spec from the table and click **Confirm**.

        <Check>QoS spec associated with volume type — limits active on all new volumes.</Check>
      </Step>
    </Steps>
  </Tab>

  <Tab title="CLI" icon="terminal">
    <Steps titleSize="h3">
      <Step title="Create a QoS spec" icon="gauge">
        ```bash title="Create QoS spec for SSD tier" theme={null}
        openstack volume qos create \
          --consumer front-end \
          --property total_iops_sec=10000 \
          --property total_bytes_sec=1073741824 \
          ssd-standard-qos
        ```
      </Step>

      <Step title="Associate with volume type" icon="link">
        ```bash title="Associate QoS spec with volume type" theme={null}
        openstack volume qos associate ssd-standard-qos ssd
        ```
      </Step>

      <Step title="Verify association" icon="circle-check">
        ```bash title="Show volume type with QoS" theme={null}
        openstack volume type show ssd
        ```

        <Check>Volume type `ssd` is now enforcing QoS limits for all new volumes.</Check>
      </Step>
    </Steps>
  </Tab>
</Tabs>

***

## Restrict Volume Type Access

By default, volume types are available to all projects. Sensitive types (e.g., encrypted
or high-performance tiers) can be restricted to specific projects:

```bash title="Make a volume type private" theme={null}
openstack volume type set --private <type-name>
```

```bash title="Grant access to a specific project" theme={null}
openstack volume type access add \
  --project <project-id> \
  <type-name>
```

```bash title="List projects with access" theme={null}
openstack volume type access list <type-name>
```

***

## Recommended QoS Values by Tier

| Tier         | total\_iops\_sec | total\_bytes\_sec      | Consumer    |
| ------------ | ---------------- | ---------------------- | ----------- |
| **NVMe**     | 50,000 – 200,000 | 4,294,967,296 (4 GB/s) | `front-end` |
| **SSD**      | 5,000 – 20,000   | 1,073,741,824 (1 GB/s) | `front-end` |
| **Standard** | 500 – 2,000      | 314,572,800 (300 MB/s) | `front-end` |

<Tip>
  Start with conservative limits and adjust based on observed workload behavior. Overly
  restrictive QoS on shared backends can throttle legitimate I/O and cause application
  timeouts.
</Tip>

***

## Next Steps

<CardGroup cols={2}>
  <Card title="Storage Tiers" href="/services/storage/storage-tiers" color="#197560">
    Configure NVMe, SSD, and HDD tier mappings and set the default volume type
  </Card>

  <Card title="Encryption" href="/services/storage/encryption" color="#197560">
    Enable at-rest encryption on volume types
  </Card>

  <Card title="Storage Backends" href="/services/storage/storage-backends" color="#197560">
    Configure and manage the underlying backend drivers
  </Card>

  <Card title="Volume Types (User)" href="/services/storage/volume-types" color="#197560">
    User guide for selecting the correct volume type for a workload
  </Card>
</CardGroup>