---
title: Troubleshooting I/O errors and read-only file systems on Dedibox Pro-2 servers
description: Learn about Linux kernel incompatibility issues affecting Dedibox Pro-2 servers and how to resolve them.
tags: dedibox server linux kernel incompatibility
dates:
  validation: 2026-09-03
  posted: 2026-09-03
---

## Problem

On machines built on the Dedibox Pro-2 line, you are encountering one or more of the following issues when running recent Linux kernels:

- Disks experience I/O packet loss
- The file system (e.g., EXT4) immediately switches to read‑only mode to protect the data
- System logs show DMA errors related to the IOMMU subsystem
- SATA link degradation (from 6.0 Gbps to 1.5 Gbps)

### Typical log messages

```
ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
EXT4-fs (md1): Remounting filesystem read-only
DMAR: ERROR: DMA PTE for vPFN ... already set
```

This page explains the incompatibility causing the problem, lists the affected machines and operating systems, and provides a workaround.

## Affected machines and operating systems

The following **Dedibox Pro-2 servers** are affected by the incompatibility issue (all based on the HP ProLiant DL320e Gen8 v2 chassis):

| Offer      |  Motherboard  |
| -------------------- | ------------------- |
| Pro-2-M-SATA         | DL320eGen8v2 (MD 2014) |
| Pro-2-M-SSD          | DL320eGen8v2 (MD 2014 SSD) |
| Pro-2-L-SATA         | DL320eGen8v2 (PRO 2014) |
| Pro-2-L-10k          | DL320eGen8v2 (PRO 2014) |
| Pro-2-L-SSD          | DL320eGen8v2 (PRO SSD 2014) |

The following **operating systems and kernel versions** are affected:

- **Debian** (kernels ≥ 6.17.13, e.g., Debian 13 "Trixie" and later versions)
- **Ubuntu** (kernels 7.x.x, e.g., Ubuntu 26.04 and later versions)
- **Proxmox VE** (kernels ≥ 6.17.13, based on Debian)

<Message type="note">
This issue affects all Debian-based distributions using recent Linux kernels with the updated Intel IOMMU handling.
</Message>

## Cause

A default change in the handling of Intel IOMMU in recent Linux kernels (Debian/Ubuntu) degrades the SATA link (drops to 1.5 Gbps, AHCI link resets) and generates I/O errors on the disk controller via the IOMMU subsystem (`DMAR: ERROR: DMA PTE …`).

## Workaround

To resolve the issue without completely disabling IOMMU virtualization (VT‑d), configure the IOMMU in passthrough mode (`iommu=pt`).

1. Open a root terminal and create a dedicated GRUB configuration file:

   ```bash
   echo 'GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT intel_iommu=on iommu=pt"' | sudo tee /etc/default/grub.d/iommu.cfg
   ```

2. Update the GRUB configuration:

   ```bash
   sudo update-grub
   ```

3. Reboot the server to apply the change:

   ```bash
   sudo reboot
   ```