Question: Does the current livecd installer inefficiently write lots of 0's to
the destination drive that it doesn't need to?
I think it might. The os.img on the F7 livecd is a 4G sparse file with about
2.3G of data. Anaconda's livecdcopy backend uses python's os.read/write. I
would guess that that means that 4G of data is getting written, when
theoretically only 2.3G needs to.
The solution that comes to mind is this-
in livecd-tools, create the os.img as a 7G (or 700G??) sparse file. Basically
just way big. Then take care to make the ext3fs be the exact correct size for
the data (i.e. 2.3G). Then, in the initramfs, just after mounting it (after
snapshotting it), do a resize2fs to 7G (or 700G).
Then when anaconda does the copy, only copy the first 2.3G of the sparse file.
It is however late in the 'day' for me, so maybe someone can chime in with
confirmation or refutation of my logic here.