Re: Hashsum mismatch prevention strategies
On Sun, May 20, 2012 at 06:30:06PM +0000, Raphael Geissert wrote:
> Goswin von Brederlow wrote:
> > Joerg Jaspert <joerg@debian.org> writes:
> > But I'm not convinced the number of files to download is actualy the
> > limiting factor:
>
> It isn't, but it adds overhead.
>
> > What is killing the pdiffs is the stop&go methodic the current
> > implementation has.
>
> I'm not even sure a new field needs to be introduced. It's just a
> matter of stating that the fields are ordered and if you have hash X
> you need all the patches mentioned in that line and the ones that follow.
Assuming that would break reprepro repositories.
>
> Additionally, I'd like an alternative way to distribute the pdiffs to
> be considered: after n days (say 2), gunzip the patches worth of one day
> and tgzip them. This not only reduces the number of requests needed to
> download all the files, but it also provides better compression. Adding an
> Index file to the tarball would be enough for apt to know which ones to
> apply and which ones to ignore.
A tar in between would complicate the code on the client, and break
backwards compatibility.
>
> > Option C)
> > =========
> >
> > The "Mirrors are going to be out-of-sync. Deal with it." option.
>
> Yes, but not by the means of another service. Sync issues also occur on
> private mirrors.
>
>
> What I had proposed on irc was a combination of a) and b), sort of:
>
> Let's call it option D:
>
> * Only the InRelease files have a constant name
> * All the other files have a date or some other sort of serial number
> appended, e.g. Packages-12042014
> * Compatibility symlinks are kept in place, but it is known they will
> be prone to race conditions (404s, even).
> * APT and others find the names of the latest available indexes from
> the InRelease file
> * InRelease becomes the one and only place at which a mirror "switches"
> from one push to another.
>
Which is basically the same I proposed as well [and what is option
C from the Ubuntu discussion].
--
Julian Andres Klode - Debian Developer, Ubuntu Member
See http://wiki.debian.org/JulianAndresKlode and http://jak-linux.org/.
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