Re: Conflict between Packages file and actual files
> Dale Scheetz <dwarf@polaris.net> writes:
>
> > This is a continuous problem. I don't know why ftp.debian.org takes so
> > long to get in sync with master, but the problem simply propogates from
> > there to all the additional mirrors. Debian is the only distribution I
> > know that depends so heavily on the accuracy of one file.
>
> This sounds like a locking problem to me.
>
> If the archive on master changes while the mirror to ftp.debian.org is
> running, then the packages file will obviously differ from the
> contents of the archive. This can continue down the chain of
> mirrors.
>
> Assuming no locking takes place, then differences become increasingly
> likely as the time taken to update the mirror increases. Another
> source of this is if the packages file on master is not updated
> immediately after a package is added. These problems will presumably
> settle if the archive is unchanged for a couple of days.
I think its a combination of these two. I think that the archive on
master being updated asynchronously with the package file is a problem
(it leads to an inconsistant archive, for one thing), and I think that
ftp.debian.org mirroring without locking is a problem.
Is there any reason why the following can't be done, and why it can't
be automated:
1) New packages are placed in the archive, without deleting the old
versions. This way, the existing Packages file and the archive remain
consistant -- if the Package file says it's there, it's there.
2) A new Packages file is generated by a script that only adds the
newest version of duplicate packages. It would be nice if this also
generated a list of older versions of duplicated packages for the next
step, but that list could also be generated as part of step one. Since
the only files listed in this new Package file are in the archive,
consistancy is maintained.
3) Delete old version of updated packages. Since these are no longer
listed in the Packages file, they can be deleted without ruining the
consistancy of the Packages file.
If this could be automated and run at a set time, then "locking" could
be achieved by scheduling it at a time when ftp.debian.org -won't- be
mirroring it. That way, ftp.debian.org is maintained as consistant.
Similarly, if the mirroring could be achieved in the same order (new
files, Packages, delete old files), then even during mirrors,
ftp.debian.org would be consistant.
--
Buddha Buck bmbuck@acsu.buffalo.edu
"Just as the strength of the Internet is chaos, so the strength of our
liberty depends upon the chaos and cacaphony of the unfettered speech
the First Amendment protects." -- A.L.A. v. U.S. Dept. of Justice
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