[plug] is rsync not good for iso updates because highlycompressed - whole image changes if only few updated files?

[Craig Foster]

Sound's 'bout right...
BTW rsync works on block comparisons, so if the CD is the same bar five
blocks, rsync knows to only download those changed blocks (after doing
heaps of comparison work)
Mitel (E-Smith) are currently trialling 5.5alpha, and the rync from
planetmirror (when it's up >:( ) is a god-send. They'd change 4-5 packages
and bam! - my modem used to melt that little bit more.

Now with rsync most good ISO sites follow this example update style:-

CD_ver_1.iso
CD_ver_2.iso
CD_ver_3.iso -> symlink to CD_current.iso
CD_current.iso

and the next version would be :-

CD_ver_1.iso
CD_ver_2.iso
CD_ver_3.iso
CD_ver_4.iso -> symlink to CD_current.iso
CD_current.iso

So all you need to do is rsync the CD_current.iso to stay, well,
current...


Regards,

Craig F.

> -----Original Message-----
> From: Bill Kenworthy [mailto:billk at iinet.net.au]
> Sent: Wednesday, April 17, 2002 9:21 PM
> To: Plug List
> Subject: Re: [plug] is rsync not good for iso updates because
> highlycompressed - whole image changes if only few updated files?
>
>
> The last Mandrake triplet saved bout a 1/3 - but a better idea is
> something like Troes rsync script - copy the iso to disk and then it
> renames and rsyncs the files individually, also makes it easy to not
> download the hundreds on megs of foreign language stuff.
>
> Also great over a modem ...
>
> BillK
>
> On Wed, 2002-04-17 at 21:22, Daniel wrote:
> > Hello All,
> > I envisaged rsync for situations like when a beta of a
> new distribution
> > release comes out and is shortly after superceded.
> > I have been told that even if few files are changed the
> isos are so highly
> > compressed these days that the files appear totally
> different to rsync and
> > thus the whole file would end up downloaded.  Is this
> correct, or is it
> > only with some distributions?
> >
> > Thanks very much,
> > Daniel.
> >
> >
> >
> > _________________________________________________________
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> > Get your free @yahoo.com address at http://mail.yahoo.com
> >
> >
>
>
>
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