Hi Mathieu!
Mathieu Othacehe <m.othac...@gmail.com> skribis:
> Let say I want to create a disk-image with one ext4 partition starting
> at offset 10M. I can write the following genimage config file:
>
> image system {
> hdimage {}
>
> partition rootfs {
> partition-type = 0x83
> image = "rootfs.ext4"
> size = 8G
> offset = 10M
> }
> }
>
> image rootfs.ext4 {
> name = "rootfs"
> ext4 {
> label = "rootfs"
> use-mke2fs = true
> }
> size = 8G
> mountpoint = "/"
> }
>
>
> and run the command:
>
> fakeroot genimage --config ~/tmp/genimage.cfg
> --rootpath=/home/mathieu/image-root/
>
> where image-root is a directory containing the result of a `guix system
> init`. The directory size is about 6GiB.
>
> It takes 8 minutes to generate this disk-image, versus 2h30 using `guix
> system disk-image`.
>
> I'm aware that this might not be a fair comparison but, I think its
> already significant.
>
> Danny, Ludo, WDYT? Could we modify "system-disk-image" to use genimage
> as a backend instead of spawning a VM?
I’m completely sold to the idea. :-)
Apparently ‘genimage’ supports many file systems, including ext[234] and
ISO9660, which are the two formats we support via ‘--file-system-type’.
It does not support Btrfs, but ‘guix system disk-image’ doesn’t support
it either so far.
Looking at ‘image-ext2.c’ reveals that genimage actually just shells out
to mke2fs. Indeed, I discovered that ‘mke2fs -d /my/root’ copies
/my/root as the image’s root directory. Likewise, for ISO, it just
shells out to ‘genisoimage’.
So I think that we could avoid ‘genimage’ altogether and implement
similar functionality for ext4/ISO in (gnu build disk-image).
WDYT?
Thanks,
Ludo’.
