[Fedora-livecd-list] Anyone using the overlay file?

[Jeremy Katz]

On Wednesday, January 21 2009, Forrest Taylor said:
> In the iso-to-disk script, one can add an overlay file.  However, I
> don't see that it is being used at all--livesys does not reference it at
> all.  It looks like the XO team passes a kernel parameter, but I haven't
> seen the code to actually use it.
> 
> My assumption is that the overlay file would be the backend storage for
> an LVM snapshot.  Has anyone actually used an overlay file?  Any ideas
> on the implementation?

The overlay gets set up in the initramfs, so see mkliveinitrd in the
mkinitrd package.  Basically what happens is that instead of creating a
file that's backed by RAM to use as our dm-snapshot device, we set up
dm-snapshot to write to the file on the USB stick instead.

Jeremy