---
title: "Run Hardware Diagnostics in Rescue Mode on a Dedicated Server"
description: "Run hardware diagnostics on your OVHcloud dedicated server using rescue mode to identify disk, RAM, or CPU failures."
url: https://docs.ovhcloud.com/en/guides/bare-metal-cloud/dedicated-servers/hardware-diagnose
lang: en
lastUpdated: 2025-10-16
---
# Run Hardware Diagnostics in Rescue Mode on a Dedicated Server

## Objective

At some point during the life of your server, you may encounter a fault due to a hardware issue. When the server is booted into the OVHcloud rescue mode, you have several diagnostic tools available to help identify faulty hardware components.

**This guide explains how to diagnose hardware issues on your OVHcloud dedicated server.**

## Requirements

- A [dedicated server](https://www.ovhcloud.com/en-gb/bare-metal/) in your OVHcloud account
- [Rescue mode](/en/guides/bare-metal-cloud/dedicated-servers/rescue-mode.md) activated

## Instructions

This guide details the tests you need to carry out to diagnose:

- Processors
- Network connection
- Memory
- Disks and partitions

### Processors

The processor test checks the working order of your server's processor, and needs about 30 minutes to run successfully. If the server crashes during this test, then it means that the processor is faulty.

```bash
WRKR=$(grep -c "^processor" /proc/cpuinfo)
stress-ng --metrics-brief --timeout 60s --cpu $WRKR --io $WRKR --aggressive --ignite-cpu --maximize --pathological
stress-ng --metrics-brief --timeout 60s --brk 0 --stack 0 --bigheap 0 
```

### Network Connection

The network connection test checks your internal and external bandwidth. This data is provided for information purposes only and is not a performance test.

```bash
ping -c 10 proof.ovh.net
for file in 1Mb 10Mb 100Mb 1Gb ; do time curl -4f https://proof.ovh.net/files/${file}.dat -o /dev/null; done
```

### Memory

The memory test checks the integrity of your server's RAM modules. If the server crashes during this test, then it means that the one or more of your RAM modules is faulty.

:::warning
Keep in mind that this test can take a long time to complete.
:::

```bash
RAM="$(awk -vOFMT=%.0f '$1 == "MemAvailable:" {print $2/1024 - 1024}' /proc/meminfo)"
memtester ${RAM}M 1
```

### Disk Health

You can use _Smartmontools_ to check the status of your disks by reading their `SMART` data. For example, to display all details of the disk labelled `nvme1n1`, enter:

```bash
smartctl -a /dev/nvme1n1
```

To learn more about the output of this command and how to interpret it, consult [the official _Smartmontools_ documentation](https://www.smartmontools.org/wiki/TocDoc).

### Disk Partitions

The partitions test is comprised of a disk access test and a file system check. The disk access test checks if the system can communicate with your server's hard drives. The file system check uses the `fsck -fy` command to check the entire file system.

To check the file system, run the following command:

```bash
fsck-fy
```

For a read test, run the command below. Replace `sd(x)` with your own values

```bash
hdparm -t /dev/sd(x)
```

## Go further

[Dedicated Server - Retrieving Databases in Rescue Mode](/en/guides/bare-metal-cloud/dedicated-servers/restore-bdd-rescue.md)

[How to verify the BMC firmware version on a Dedicated Server](/en/guides/bare-metal-cloud/dedicated-servers/bmc-fw-update.md)

Join our [community of users](https://community.ovhcloud.com/).