rsync'ing .iso

[Jeremy Katz]

On Monday, March 02 2009, Martin Langhoff said:
> On Mon, Mar 2, 2009 at 4:23 PM, Jeremy Katz <katzj at redhat.com> wrote:
> > On Sunday, March 01 2009, Tomeu Vizoso said:
> >> I see that some projects distribute xdelta3 files of their .iso files
> >> and others use rsync, but the .iso we generate with the fedora livecd
> >> tools don't compress almost anything by that. It's because we miss a
> >> switch like --rsyncable somewhere?
> >
> > squashfs, unfortunately, isn't rsync friendly.  And since the live
> > images depend on squashfs to fit on a CD, there's not much we can do[1]
> 
> ISOs themselves are not rsync friendly, but jigdo does the needed
> magic. Perhaps squashfs can be tamed with jigdo somehow?

ISOs are actually very rsync friendly if you're using a consistent
process for creating them.  jigdo is more useful for the case of "some
of the bits already exist mirrored and you don't want to have to carry
around lots of copies of the bits on the mirrors"

With the way squashfs works, jigdo really doesn't help at all

Jeremy