Re: standard apt/yum meta-data format
Steinar H. Gunderson wrote:
> On Fri, Jul 02, 2004 at 05:38:52PM -0700, Mike Fedyk wrote:
> > Hopefully it's multiple files will allow apt-get update to download only
> > the changes instead of the entire list over and over.
>
> Note that "more files" usually mean "more load on the mirrors" -- you
> definitely do not want too much splitting of such files either. (Yes, it
> might sound harsh to the people on low-bandwidth lines, I know. :-) )
Depends on how you do it. With some sensible strategy, has only to fetch
two (usually small) files from the mirror instead of one large one.
My approch on this would be to stay with a single Packages file, but
provide _cumulative_ diffs from earlier versions, and a index file for
those. So we would have
Packages.gz
Packages-cdiff.index
Packages-cdiff.2004-07-02.gz
Packages-cdiff.2004-07-01.gz
Packages-cdiff.2004-06-30.gz
...
Keeping the cdiffs of the last two weeks should be good enough.
With this scheme, current apt-get implementations simply continue
to use Packages.gz. New apt-get would fetch the index file first,
look up the proper cdiff name noted in it, fetch the cdiff and apply
it to the host's Packages file. Without a matching cdiff, it would
fall back to the old method as well.
> This is
> also the primary reason why using rsync for apt is usually discouraged.
rsync is a completely different beast than a simple file transfer.
Thiemo
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