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Re: shutting down httpredir.debian.org?

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On Thu, Apr 14, 2016 at 11:49:12AM +0200, Bastian Blank wrote:
> On Thu, Apr 14, 2016 at 09:02:18AM +0000, Peter Palfrader wrote:
> > You could argue (and I have), that that file-based redirects are not
> > ideal if your update is downloading lots of little files.  The latency
> > hit of many redirects is non-trivial.
>
> My last test showed problems with httpredir returning different mirrors
> with each request, which made keep-alive completely impossible.
> Downloading all the stuff during a cdebootstrap run from a real mirror
> took 5s[1], from httpredir at least 20s[2].

Well, its kinda the point of httpredir to give you different mirrors[1]
(which ideally all have the same state – if not you get the hashsum
mismatches). That allows "long living" clients like apt to talk to the
different mirrors at the same time (proper keep-alive and pipelining to
them all). One-shot clients like wget which debootstrap is using are
obviously not doing either (with the same argument its also unwise to
use a https mirror for those clients).

It is frequently said that apt should "just" open multiple connections
to the same mirror and stuff like apt-fast sells bigtime on this, but as
a categorical imperative[2] it makes no sense: Of course you are
speeding up your throughput if you add more cars to a traffic jam – but
only as long as other people don't use the same strategy. If they all do
it the traffic jam is even bigger and its actually slower for everyone.

[1] Which is not to say that it must be httpredir which gets us such
a list, but it was possible and someone implemented it.
[2] I know, browsers do it all the time – but most websites are build
dynamic requiring non-trivial time on the server to process so it kinda
makes sense as a workaround; repositories are pretty static) and the
HTTP1.1 spec actually allows it. It gets slightly more sensible with
HTTP2 now – at least server/proxy implementors can't say pipelining is
too much state keeping to implement properly anymore. ;)


Best regards

David Kalnischkies

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Thread

shutting down httpredir.debian.org? Peter Palfrader <weasel@debian.org> - 2016-04-12 09:10 +0200
  Re: shutting down httpredir.debian.org? Raphael Hertzog <hertzog@debian.org> - 2016-04-12 09:40 +0200
    Re: shutting down httpredir.debian.org? Peter Palfrader <weasel@debian.org> - 2016-04-12 10:00 +0200
      Re: shutting down httpredir.debian.org? Cord Beermann <cord@debian.org> - 2016-04-12 12:30 +0200
      Re: shutting down httpredir.debian.org? Christian Rohmann <crohmann@netcologne.de> - 2016-04-12 13:00 +0200
        Re: shutting down httpredir.debian.org? Raphael Hertzog <hertzog@debian.org> - 2016-04-13 10:30 +0200
          Re: shutting down httpredir.debian.org? Christian Rohmann <crohmann@netcologne.de> - 2016-04-14 10:00 +0200
            Re: shutting down httpredir.debian.org? Peter Palfrader <weasel@debian.org> - 2016-04-14 11:10 +0200
              Re: shutting down httpredir.debian.org? Bastian Blank <waldi@debian.org> - 2016-04-14 12:10 +0200
                Re: shutting down httpredir.debian.org? David Kalnischkies <david@kalnischkies.de> - 2016-04-14 15:40 +0200
                Re: shutting down httpredir.debian.org? Tollef Fog Heen <tfheen@err.no> - 2016-04-15 06:50 +0200
                Re: shutting down httpredir.debian.org? Ondřej Surý <ondrej@sury.org> - 2016-04-25 14:30 +0200
                Re: shutting down httpredir.debian.org? Tollef Fog Heen <tfheen@err.no> - 2016-04-25 14:50 +0200
                Re: shutting down httpredir.debian.org? Ondřej Surý <ondrej@sury.org> - 2016-04-25 15:10 +0200
                Re: shutting down httpredir.debian.org? David Kalnischkies <david@kalnischkies.de> - 2016-04-25 15:50 +0200
                Re: shutting down httpredir.debian.org? Peter Palfrader <weasel@debian.org> - 2016-04-25 17:40 +0200
              Re: shutting down httpredir.debian.org? anarcat <anarcat@orangeseeds.org> - 2016-04-14 17:00 +0200
                Re: shutting down httpredir.debian.org? Charles Plessy <plessy@debian.org> - 2016-04-15 03:20 +0200
                Re: shutting down httpredir.debian.org? Paul Wise <pabs@debian.org> - 2016-04-15 04:00 +0200
                Re: shutting down httpredir.debian.org? Tollef Fog Heen <tfheen@err.no> - 2016-04-15 07:00 +0200
          Re: shutting down httpredir.debian.org? Christian Rohmann <crohmann@netcologne.de> - 2016-04-14 14:00 +0200
            Re: shutting down httpredir.debian.org? Raphael Hertzog <hertzog@debian.org> - 2016-04-14 17:00 +0200
              Re: shutting down httpredir.debian.org? Christian Rohmann <crohmann@netcologne.de> - 2016-04-19 13:50 +0200
    Re: shutting down httpredir.debian.org? Paul Wise <pabs@debian.org> - 2016-04-12 18:30 +0200
  Re: shutting down httpredir.debian.org? Lucas Nussbaum <lucas@debian.org> - 2016-04-12 10:50 +0200
  Re: shutting down httpredir.debian.org? Raphael Geissert <geissert@debian.org> - 2016-04-12 14:00 +0200
    Re: shutting down httpredir.debian.org? Ben Hutchings <ben@decadent.org.uk> - 2016-04-12 15:10 +0200
    Re: shutting down httpredir.debian.org? Peter Palfrader <weasel@debian.org> - 2016-04-12 15:30 +0200
      Re: shutting down httpredir.debian.org? Raphael Geissert <geissert@debian.org> - 2016-04-13 14:30 +0200
    Re: shutting down httpredir.debian.org? Donald Norwood <dnorwood@portalus.com> - 2016-04-12 19:20 +0200
      Re: shutting down httpredir.debian.org? Donald Norwood <dnorwood@portalus.com> - 2016-04-12 22:50 +0200

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