---
title: "How to configure a software RAID on a node"
description: "Find out how to configure and manage a software RAID on an OpenStack Ironic node in OPCP"
url: https://docs.ovhcloud.com/de/guides/hosted-private-cloud/opcp/how-to-setup-softraid-on-node
lang: de
lastUpdated: 2026-02-06
---
# How to configure a software RAID on a node

## Objective

This guide explains how to configure and manage a **software RAID** on an OpenStack Ironic baremetal node in your OPCP environment.

Software RAID allows you to create a redundancy configuration at the software level, without requiring a dedicated hardware RAID controller. This solution is particularly useful to improve the availability and storage performance of your instances.

**This guide covers:**

- Configuring software RAID via the Ironic agent interface
- Verifying the RAID configuration
- Best practices for managing software RAID

:::warning

Software RAID must be configured **before** deploying an instance on the node.
Once an instance has been deployed, changing the RAID configuration requires deleting the instance and reconfiguring the node.
Creating or modifying a RAID array erases the data present on the disks used.

Monitoring of the software RAID is the responsibility of the end customer: we do not have access to the deployed instance to manage monitoring. You should configure alerting (for example using the `mdadm --monitor` command) and integrate this monitoring into your existing monitoring tools.

:::

## Requirements

Before you begin, make sure you have the following:

- An active [OPCP](https://www.ovhcloud.com/en-gb/hosted-private-cloud/onprem-cloud-platform/) service.
- Access to **[Configured OpenStack CLI](/de/guides/hosted-private-cloud/opcp/how-to-use-api-and-get-credentials.md)** with the required permissions (`clouds.yaml` or environment variables).
- The **admin** role and/or nodes transferred into your project.
- An available node (status `available`) or a node in maintenance mode.
- A **Linux** (GNU/Linux) system image is required for the instance. This image must include the `mdadm` package or allow its installation. VMware appliances and Windows operating systems, for example, are not compatible with this procedure.
- Basic knowledge of OpenStack Ironic and baremetal node management.

## Why use software RAID?

Software RAID provides several benefits in an OPCP environment:

- **Data redundancy**: Protection against data loss in the event of a disk failure.
- **Performance improvement**: Distribution of read/write operations across multiple disks.
- **Lower cost**: No need for a dedicated hardware RAID controller.

## Instructions

### 1. Check the disks available on the node

Before configuring RAID, you must identify the disks available on your node.

**List available nodes:**

```bash
openstack baremetal node list
```

**Check the node hardware properties:**

```bash
openstack baremetal node show <node-id>
```

### 2. Enable maintenance mode

Before any configuration change, put the node in **maintenance mode**:

```bash
openstack baremetal node maintenance set <node-id> --reason "Software RAID configuration"
```

### 3. Supported RAID level [](#)
Ironic supports several software RAID levels. The following values are accepted in the JSON configuration:

| RAID level | JSON value | Description | Minimum number of disks |
| ---------- | ---------- | ----------- | ----------------------- |
| **RAID 1** | `"1"`      | Mirroring   | 2                       |

:::warning

**Important constraint**: The first logical disk with `is_root_volume: true` **must be in RAID 1**. Other RAID levels (RAID 0, 5, 6, 10, etc.) are not allowed for the root volume.

:::

It is therefore only possible to use RAID 1 for the instance deployment.

### 4. Configure software RAID

Ironic allows you to configure software RAID via the **agent** interface. This configuration is applied automatically when an instance is deployed.

#### 4.1. Check and enable the agent interface if necessary [](#)
Before configuring RAID, check the RAID interface currently configured on the node:

```bash
openstack baremetal node show <node-id> -f json | jq '.raid_interface'
```

If the output is `null` or different from `"agent"`, enable the agent RAID interface:

```bash
openstack baremetal node set <node-id> --raid-interface=agent
```

#### 4.2. Create the RAID configuration file

Create a JSON file containing the desired RAID configuration. The following example creates a RAID 1 (mirroring) array with two disks:

```bash
cat > /tmp/raid1.json <<EOF {
  "logical_disks": [{
    "controller": "software",
    "size_gb": "MAX",
    "raid_level": "1",
    "is_root_volume": true,
    "physical_disks": [
      {"size": "<1000"},
      {"size": "<1000"}
    ]
  }]
}
EOF
```

:::info

The `"size": "<1000"` parameter in `physical_disks` automatically selects disks smaller than 1000 GB. You can adjust this value according to the size of your disks or use other selection criteria.

:::

#### 4.3. Apply the RAID configuration

Once the configuration file has been created, apply it to the node:

```bash
openstack baremetal node set <node-id> --target-raid-config /tmp/raid1.json
```

#### 4.4. Check the RAID configuration

To check the RAID configuration applied on a node:

```bash
openstack baremetal node show <node-id> -f json | jq '.target_raid_config'
```

### 5. Disable maintenance mode

Once the RAID configuration is complete, disable maintenance mode:

```bash
openstack baremetal node maintenance unset <node-id>
```

### 6. Deploy an instance on the configured node

Once RAID has been configured, you can deploy an instance on the node:

```bash
openstack server create \
  --image <image-name> \
  --flavor <flavor-id> \
  --key-name <keypair-name> \
  --nic net-id=<network-id> \
  --availability-zone "nova::<node-id>" \
  <instance-name>
```

:::tip

To make sure that your instance is deployed on the node configured with RAID, use the availability zone `nova::<node-id>`.

:::

### 7. Check the RAID configuration after deployment

Once the instance is deployed, you can check the RAID configuration from within the instance:

**Check RAID devices:**

```bash
cat /proc/mdstat
```

**Example output:**

```
Personalities : [raid1] [raid10] [linear] [multipath] [raid0] [raid6] [raid5] [raid4]
md0 : active raid1 sda[0] sdb[1]
      500G 0 blocks super 1.2 [2/2] [UU]

unused devices: <none>
```

**Check detailed information for a RAID device:**

```bash
mdadm --detail /dev/md0
```

## Summary of main commands

| Action                                | Command                                                                                                                                                                       |
| ------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| List nodes                            | `openstack baremetal node list`                                                                                                                                               |
| Enable maintenance mode               | `openstack baremetal node maintenance set <node-id>`                                                                                                                          |
| Check RAID interface                  | `openstack baremetal node show <node-id> -f json \| jq '.raid_interface'`                                                                                                     |
| Enable agent RAID interface           | `openstack baremetal node set <node-id> --raid-interface=agent`                                                                                                               |
| Apply RAID configuration              | `openstack baremetal node set <node-id> --target-raid-config /tmp/raid1.json`                                                                                                 |
| Check RAID configuration              | `openstack baremetal node show <node-id> -f json \| jq '.target_raid_config'`                                                                                                 |
| Disable maintenance mode              | `openstack baremetal node maintenance unset <node-id>`                                                                                                                        |
| Deploy an instance                    | `openstack server create --image <image-name> --flavor <flavor-id> --key-name <keypair-name> --nic net-id=<network-id> --availability-zone "nova::<node-id>" <instance-name>` |
| Check RAID status (from the instance) | `cat /proc/mdstat`                                                                                                                                                            |

## Best practices

- **Always configure RAID before deployment**: The configuration must be done on a node with no active instance.
- **Use maintenance mode**: Always put the node in maintenance before making any changes.
- **Regular backups**: RAID is not a backup solution; make regular backups of your data.
- **Monitor the RAID**: Set up RAID monitoring (for example with `mdadm --monitor`) and integrate alerts into your monitoring tools to quickly detect any degradation or disk failure.

## Limitations and considerations

- **Performance**: Software RAID can have an impact on CPU performance compared to hardware RAID.
- **Compatibility**: Not all operating systems support all software RAID levels.
- **Rebuild**: Rebuilding a RAID array after replacing a disk can take a long time and consume resources.

## Troubleshooting

| Error                                                                            | Cause                                                             | Solution                                                                                        |
| -------------------------------------------------------------------------------- | ----------------------------------------------------------------- | ----------------------------------------------------------------------------------------------- |
| `Driver redfish does not support raid (disabled or not implemented). (HTTP 404)` | The RAID interface is not configured as `agent`                   | See the [section 4.1 - Check and enable the agent interface if necessary](#check-agent)         |
| `Software RAID Configuration requires RAID-1 for the first logical disk`         | The first logical disk with `is_root_volume: true` must be RAID 1 | Use RAID 1 for the root volume.<br /> See the [section 3 - Supported RAID levels](#raid-levels) |

## References

- [OpenStack Ironic Documentation - RAID Configuration](https://docs.openstack.org/ironic/latest/admin/raid.html)
- [mdadm Documentation](https://linux.die.net/man/8/mdadm)
- [OPCP Guide - Node lifecycle](/de/guides/hosted-private-cloud/opcp/node-lifecycle.md)

## Go further

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