Re: Speeding Up APT - Project Idea
On Wed, Mar 23, 2011 at 11:27:48AM +0100, Goswin von Brederlow wrote:
> Ishan Jayawardena <udeshike@gmail.com> writes:
>
> > Hi Michael, Hi all,
> >
> > As you may remember, I talked with you about integrating debdelta into
> > apt-get, on the IRC. I found it interesting and therfore, hope to come
> > up with a project proposal out of it.
>
> It might make more sense to look into zsync and implement the missing
> support to "look into .deb files". The .zsync files could then be
> generated by DAK and could be used with any http mirror.
The debdelta integration is a good solution for stable and for
security updates IMO. We know it works well and its stable since some
time and well understood. But not that great for unstable. For known
version updates (like security updates) it should produce smaller
deltas than zsync too.
> The advantage of zsync would be that it can download the delta between
> any 2 versions of a package or between a damaged and actual file of the
> package. With debdelta the mirror would have to contain the exact diff
> between the local version in the apt cache and the current version. That
> would be quite unworkable for unstable. Ad the deltas would be far
> larger than the .zsync files.
The zsync based delta would indeed be preferable (if we can make it
work!). There is even working code around around it here:
https://code.launchpad.net/~felix-feyertag/apt-sync/main
But we never quite finished it and it needs someone to really look
into it again and see whats missing. More research around it is
needed, like how well does the deltas work, what blocksizes to use,
the http range request approach may turn out to be problematic with
various proxies etc. I would love to see someone working on it too,
but I consider it a bit more experimental then the debdelta approach.
Cheers,
Michael
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