24

I have a qcow2 image that I use to boot an installation of linux using QEMU; I would like to place the contents of that image directly onto a physical hard drive so that I can boot to that linux installation directly from my desktop. I would like to do something like dd if=my-qcow2.img of=/dev/sdb. However, this will clearly not work since qcow2 does not store the contents of the virtual disk in logical order within the qcow2 file. Any suggestions?

1 Answer 1

24

QEMU comes with the qemu-img program to convert between image formats.

qemu-img convert -f qcow2 -O raw my-qcow2.img /dev/sdb
4
  • 2
    Pay attention that the QCOW2 format is Compressed! That means a 200GB QCOW2 image can convert into a 500GB hard drive... That may cause the "device is too small" error you are receiving imho Jul 13, 2019 at 18:29
  • 8
    Old question, but: qemu-img nowadays features the dd subcommand, which I found slightly easier to understand. For example: qemu-img dd -f qcow2 -O raw bs=4M if=/vm-images/image.qcow2 of=/dev/sdd1. It works just like the usual standalone dd program.
    – Binarus
    May 14, 2020 at 14:42
  • It's failing with error while converting raw: Cannot grow device files error.
    – recolic
    Apr 17, 2023 at 22:56
  • 1
    @recolic That means that the destination disk is smaller than the uncompressed image. Jul 1, 2023 at 4:54

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .