How to Mount a QCOW2 Disk to a Linux Machine

This guide explains how to mount a qcow2 disk image to a Linux machine. While the initial command might differ for other distributions, the core steps remain consistent. This example is tailored for Debian 12.

1. Install QEMU Tools

First, install the necessary QEMU utilities, which provide the qemu-nbd tool.

sudo apt install qemu-utils

2. Load the NBD Kernel Module

Load the NBD (Network Block Device) kernel module. The max_part parameter specifies the maximum number of partitions the NBD device can expose. Set it to a value suitable for your needs, for example, 2 if you expect up to two partitions.

sudo modprobe nbd max_part=2

3. Connect QCOW2 as a Network Block Device

Now, connect your qcow2 image as a network block device. Replace /path/to/snap-vol-20GB.qcow2 with the actual path to your qcow2 file. This command makes the qcow2 image accessible via /dev/nbd0.

sudo qemu-nbd --connect=/dev/nbd0 /path/to/snap-vol-20GB.qcow2

4. List Partitions

To identify the partition you want to mount, list the partitions available on the connected NBD device:

lsblk /dev/nbd0

This command will show you the partition layout of your qcow2 image (e.g., nbd0p1, nbd0p2).

5. Mount the Partition

Create a mount point (if it doesn't already exist) and then mount the desired partition. In this example, we're mounting /dev/nbd0p1 to /mnt/data/. Adjust the partition name (nbd0p1) and mount point (/mnt/data/) as needed.

sudo mkdir -p /mnt/data/
sudo mount /dev/nbd0p1 /mnt/data/

6. Teardown

Once you're finished accessing the disk, it's crucial to unmount it and disconnect the NBD device to free up resources. Follow these steps in reverse order:

sudo umount /mnt/data/
sudo qemu-nbd --disconnect /dev/nbd0
sudo rmmod nbd