Fedora Unity release

Kam Leo kam.leo at gmail.com
Mon Feb 18 21:59:05 UTC 2008

On Feb 18, 2008 10:17 AM, Bill Davidsen <davidsen at tmr.com> wrote:
> David Boles wrote:
> > Hash: SHA1
> >
> > Bill Davidsen wrote:
> > | Tom Horsley wrote:
> > |> On Sun, 17 Feb 2008 09:55:55 -0500
> > |> Bill Davidsen <davidsen at tmr.com> wrote:
> > |>
> > |>> That's my read on it, when a release first comes out the servers get
> > |>> hammered harder with jigdo than bittorrent. The sole advantage of
> > |>> jigdo is use of protocols which are more likely to be permitted
> > |>> through firewalls, and conceptually allowing a server to have only
> > |>> part of the larger image taking up disk space. I doubt that any
> > |>> machine which can't hold the whole image should be a server anyway,
> > |>> that's just my take on it, opinion rather than fact.
> > |>
> > |> Yep. I think jigdo will be ready for prime time when it can use
> > |> bittorrent as a download protocol, and all users who chose to do
> > |> so can seed the rpms they already have downloaded and cached on
> > |> their machine. That gets the advantages of both, and since "popular"
> > |> rpms are (by the definition of popular) installed on more machines,
> > |> the rpms in the greatest demand will also have the greatest supply
> > |> of torrent servers, thus giving the best of both worlds (and no, I'm
> > |> not volunteering to do any of the work to make this happen - this
> > |> is just my fantasy :-).
> > |>
> > | I share it. Even if the servers just offered bittorrent for the whole
> > | image download and then used jigdo for image to image upgrades it would
> > | make things better for the servers, less load when something new comes
> > out.
> > |
> >
> >
> > It appears that none of you in this thread understands just how jigdo
> > really works.
> >
> Translation: if you don't think my idea is great, you are too stupid or
> ignorant to understand. Never "you have pointed out limitations in the
> application."
> > 1: The Fedora-Unity site only offers the new iso template and
> > configuration files to run this particular jigdo. They do *not* provide
> > any of the rpm packages.
> >
> I'm not sure why you think that isn't clear, neither do site offering a
> .torrent file for download.
> > 2: You, *if* you have a set of CDs or a DVD, offer the packages that have
> > not been updated from them, and they are copied and placed into the new
> > iso template.
> >
> In spite of everything I (and others) have posted, you still want to
> redefine the problem by postulating that we have the DVD already, when
> several of us have noted that's not the case.
> > 3: The packages that *have* been updated are downloaded using the same
> > mirrors that the regular Fedora updates come from and are placed into the
> > iso template.
> >
> Right, one...at...a...time with each package coming from a site which
> may be slow for the technical reasons I noted in an earlier post you're
> ignoring. Whereas bittorrent pulls from many sites in parallel,
> minimizing the impact of a single slow site.
> > 4: When jigdo finishes you have a shiny new DVD iso or a set of CD isos
> > with unchanged packages, provided by you, and the changed packages
> > provided by the Fedora mirrors.
> >
> I'll take your word for the "finishes," it may happen. And of course
> after you manually tell it to retry getting packages some number of times.
> > Not at all like bittorrent. More like rsync.
> >
> Right, same "one file at a time" deal. Not that it doesn't have it's
> uses, just that jigdo is an update tool which is not well suited to
> pulling a whole image. The fact that a poster said he got 9alpha1 in
> "only 16 hours" should be a hint.
> > This system was not intended to download a whole DVD or set of CDs. It
> > makes updated media.
> >
> Exactly, but people need a way to get the original before they can
> update, and that's why there's BT. Only there isn't BT, so people waste
> time trying to use the wrong tool because there is no other.
> > For me? A DVD takes, depends, one and one-half to 2 hours. CDs about
> > twenty minutes. Bittorrent takes forever.  ;-)
> >
> Excuse me if I don't believe you pull the whole DVD in that time, at
> least not from the dog-slow servers used by the public. BT runs about
> 10x faster for any given image if you have the bandwidth, jigdo runs at
> the speed of the slowest server it can find by random search.

10X is only available for a short interval. Torrent speed relies upon
the contributed bandwidth of the clients in a swarm. The mininum
required give-back bandwidth for each client is 4K bits per second. In
order for you to obtain your 10X download speeds the torrent clients
need to be numerous, file fragments must be widely and uniformly
distributed, and each client's network connection must be fast and
reliable. The highest bandwidth is obtained within the first few weeks
of a distro's release. Speeds tend to drop off rapidly after the
initial release buzz has worn off. You might be lucky and get 80-100K
bits/second speeds after the initial rush has passed by.

Bottom line: Torrents need lots of clients for speed. Jigdo may
actually provide better results after the buzz has worn off.

> --
> Bill Davidsen <davidsen at tmr.com>

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