yum differential updates

Robert Mortimer rmortimer at bluechiptechnology.co.uk
Mon Apr 10 16:02:08 UTC 2006


> On Mon, 2006-04-10 at 23:24 +1000, David Timms wrote:
> > I haven't tried this but I thought I might: from my reading of
> the rsync
> > protocol, it can efficiently sync two identically named files,
> even when
> > the data moves around within the file. This is done by taking a rolling
> > hash and comparing at each end.
> >
> > An rpm update for say FC5, would be very likely to have very small
> > changes - ie bug fixes, but since compiles would otherwise be
> the same I
> > imagine it would be a good candidate for efficient rsyncing.
> >
> > I was thinking that the changes for even openoffice, or the
> kernel might
> > not be so great even between major release eg FC4 to FC5. Some
> rpm might
> > hardly change eg docs and tzdata, or the language packs for openoffice
> > or kde etc.
>
> The problem is that even if it is a small change, all the source gets
> recompiled, so the resultant binaries could be different, and different
> enough to cause large amounts of little changes.  This is because we
> don't just spin the same binaries with say a new doc file or something
> like that.  Little changes just from a recompile add up quickly.
>
On the subject of bandwidth, would it be possible to produce install
ISO images once a month that included latest updates? Images would be
dished out by bit-torrent and for each install would reduce load on
the main servers at time of first update.

Alternately produce an update repository torrent with instructions to
produce a local update repository. Each day a new tracker would
be produced and used to update the local update repository.
This could be automated as a script.

Rob Mortimer
(Some bloke)




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