Dracut, dmsquash, and overlays

[Will Woods]

On Mon, 2014-07-28 at 21:26 -0500, Major Hayden wrote:
> On Jul 28, 2014, at 17:11, Will Woods <wwoods at redhat.com> wrote:
> 
> > Since your systems have lots of RAM, why not just use a regular ext4
> > filesystem image as your root filesystem? Then you don't need to worry
> > about blowing up the overlay at all.
> 
> Are you suggesting an ext4 r/w filesystem stored in RAM?  I haven't
> seen how to do that in dracut with the existing scripts.

Any filesystem image *should* work as a live image. dmsquash-live images
get handled specially, but plain ext4 (or squashfs, or cramfs, or btrfs,
or whatever) should work just as well. 

See dmsquash-live-root.sh, where (if given a filesystem image) it checks
the filesystem type and mounts it accordingly:

https://github.com/haraldh/dracut/blob/master/modules.d/90dmsquash-live/dmsquash-live-root.sh#L64

Or just try it:

   root=live:http://host.your.sys/path-to/ext4.img

If this doesn't work, that's a bug in dracut, and should be filed
accordingly.

-w