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Re: Apt and rsync... I know...

On Sun, Jan 18, 2004 at 01:43:30AM -0700, Doug Holland wrote:

> That's it.  One piddly little patch, which most likely affected one line of 
> source code, required me to waste 2.5 hours of dialup bandwidth downloading 
> a .deb file that's almost identical to the one I downloaded yesterday.  Am I 
> the only one who finds this irritating?

This all makes sense, except for the "required" part.

> I remember the reason why apt is not currently doing rsync is because it hogs 
> I/O and CPU cycles on the Debian servers.  That's a valid reason, but surely 
> there are ways around it.

Surely.  First, arrange for all of the packages in Debian to be compressed
using gzip --rsyncable.  Then, find a server with gobs of disk, network, I/O
and CPU resources, mirror the Debian archive, and run an anonymous rsync
server.  Then, write an rsync method for apt, or use rproxy, or whatever.

That is the approximate order in which things would need to happen.  It's a
bit early in the process to be pointing fingers at apt.

> I suggest that rsync files be precalculated, so rsync downloads don't have to 
> be crunched on the fly.  The servers would store .deb files - foo-x.y.z.deb, 
> and they would store the rsync diffs between it and the previous version - 
> foo.x.y.z-1_x.y.z.rsdeb.  That way, if the user doing an apt-get upgrade has 
> the previous .deb file in his cache, apt would download the rsync diff file 
> instead of the full .deb, saving loads of bandwidth, and since the rsyncs are 
> precomputed and cached, the servers don't get hosed.
> Am I totally off base suggesting this?

Yes.  It shows that you haven't read the previous discussions that you
alluded to at the beginning of your message, because they explain why this
is not a good solution.

Bug #128818 has some starting points.

 - mdz

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