I'm on garuda linux. How do I - Perplexica

I'm on garuda linux. How do I mount /media/garyrust/VM-win/VM/images/MX-10-2025-07-18-2251.qcow2 so I can dd to the /dev/loop. Use nbd

Sources

How to mount an ISO file in VirtualBox on Windows 11, 10

Garuda Linux - your opinionated Linux distro

3 Ways to Transfer Files Between a Virtual Machine and PC on VMware and VirtualBox

Convert ISO images to docker images

How to Create and Use an SSH Tunnel for Secure Remote Access

Answer

To mount a QCOW2 virtual machine disk image using an NBD (Network Block Device) device and then use dd to write it to a loop device, follow these steps:

Step 1: Install Required Packages

Ensure you have the necessary packages installed on Garuda Linux: bash sudo pacman -S nbd qemu-utils

Step 2: Create an NBD Device

The NBD kernel module will expose the QCOW2 image as a block device. First, load the module if it's not already loaded: bash sudo modprobe nbd max_part=16

Next, create an NBD device (e.g., /dev/nbd0): bash sudo qemu-nbd -c /dev/nbd0 /media/garyrust/VM-win/VM/images/MX-10-2025-07-18-2251.qcow2

Step 3: List and Select the Partition (if applicable)

If your QCOW2 image contains partitions, you may need to select a specific partition. Use fdisk or lsblk to list available partitions: bash sudo fdisk -l /dev/nbd0

Then, connect to the desired partition (e.g., /dev/nbd0p1): bash sudo qemu-nbd -b /dev/nbd0p1 # Replace p1 with your partition number

Step 4: Find the Loop Device

The NBD device will now appear as a loop device (e.g., /dev/loopX). List available loop devices to find it: bash sudo losetup -l

Step 5: Attach the NBD Device to a Loop Device

Attach the NBD device to a loop device: bash sudo losetup /dev/loop0 /dev/nbd0 # Replace loop0 with your desired loop device

Step 6: Verify the Loop Device

Check that the loop device is properly attached and its size matches the QCOW2 image: bash sudo fdisk -l /dev/loop0

Step 7: Use dd to Write to /dev/loop

Now, you can use dd to write the contents of the loop device to another block device (e.g., a USB drive or another disk): bash sudo dd if=/dev/loop0 of=/path/to/output.img bs=4M status=progress Replace /path/to/output.img with your desired output path.

Step 8: Disconnect the NBD and Loop Device (when done)

When finished, safely disconnect the loop device and NBD device: bash sudo losetup -d /dev/loop0 sudo qemu-nbd -d /dev/nbd0

Notes:

  1. Permissions: Ensure you have read/write permissions for the QCOW2 image and output file.
  2. Backup: Always back up important data before performing operations like dd.
  3. Error Handling: If errors occur, check logs (journalctl -xe or /var/log/syslog) for clues.
  4. Alternative: If you don't need to partition the image, you can skip steps 3 and 5 and directly use /dev/nbd0p1 (or similar) with dd.

To convert QCOW2 files, the most common and versatile method is using the qemu-img tool, which supports converting between various virtual disk image formats.

Basic Conversion Using qemu-img

  • Install the qemu-utils package if not already installed (e.g., apt-get install qemu-utils on Ubuntu).
  • Use the following command to convert a disk image to QCOW2 format from another format: 
    qemu-img convert -f <existing_format> -O qcow2 <input_file> <output_file>.qcow2

Example for QCOW2 to raw

  • Conversely, to convert QCOW2 to another format, change the -O option to the desired output format, for example, to raw: 
    qemu-img convert -f qcow2 -O raw <input_file>.qcow2 <output_file>.img

Supported Formats

This tool supports many formats, including raw, qcow2, vmdk (VMware), vdi (VirtualBox), vhd (Hyper-V), and qed.

Example for QCOW2 to VMDK (VMware)

  • Convert QCOW2 to VMDK using: 
    qemu-img convert -f qcow2 -O vmdk <input_file>.qcow2 <output_file>.vmdk
  • Optionally, use VMware tools like vmkfstools to optimize the VMDK for ESXi.

Notes

  • The -f flag sets the input format; it might be optional as qemu-img tries to auto-detect the format.
  • The process can be used to convert disk images for different hypervisor environments.
  • For mounting or extracting filesystem content from QCOW2, additional tools like virt-tar-out can be used.

This command-line tool offers a straightforward approach to convert and manage QCOW2 disk images between different virtual machine image formats.[1][2][3][4][6]

1
2
3
4
5
6
7
8