Maybe try first
qemu-img resize
then use qemu-img convert
On Fri, 21 Jun, 2024, 20:18 Sven Ott, <sven....@fau.de> wrote:
> Hi, I want to mount a VM image to a loop device and give it some excess
> space.
>
> To do so, I download a .qcow2 file, add some 0 bytes with truncate, and
> then convert the image from QCOW2 to RAW format with qemu-img convert,
> like so:
>
> ```
>
> GUEST_IMG=focal-server-cloudimg-amd64
>
> wget https://cloud-images.ubuntu.com/focal/current/$GUEST_IMG
>
> truncate -s 5G $GUEST_IMG.img
>
> qemu-img convert -f qcow2 -O raw $GUEST_IMG.img $GUEST_IMG.raw
>
> ```
>
> The problem is that the convert command throws away the 0-bytes which
> have been appended earlier, leaving me with a .raw image of the original
> size. As per the man page, the resulting image can be optionally
> compressed with the -c flag, indicating that not providing said flag
> would lead to an uncompressed resulting image.
>
> I'm on Debian on x86_64; I've tried the qemu-img version 6.2 and 8.2
> unsuccessfully so far.
>
> Any help would be appreciated!
>
> Sven
>
>
>
>
