Re: Bittorrent distribution of cdimages
On Mon, 6 Oct 2003, jason andrade wrote:
> On Sun, 6 Oct 2002, Goswin von Brederlow wrote:
>
> > With bittorrent you have to have a running tracker. You also need
> > clients connected to the tracker that feed the data. That means each
> > mirror would have to run a bittorrent client on their local image.
>
> does every mirror run a tracker ? or does each project run a tracker ?
> or both ?
There needs only to be one tracker Debian-wide.
> e.g do i run a tracker for just debian cd files ? or does someone in the
> debian project run a 'debian wide' tracker with pointers to mirrors?
>
> or can i as a mirror run a tracker for all the different files i'd
> like to make available, not just within the debian cd archive ?
>
> and can you outline how i run a BT client on local images given that:
>
> o there are multiple releases
> o there are multiple architectures within each release
> o there are multiple images within each architecture
This is where it gets hard. Because besides running the tracker (which is
only done at a single point (... of failure)) each file needs to be
"seeded" in BT terminology. That means running the BT client when you
already have the file.
Basically the BT system is a metafile (called torrent) and a tracker. The
torrent is coupled to one file (or a fileset, but I'll assume single file
case here) that when a user first downloads the torrent via http then can
run the BT client on the torrent and have that generate the full file
(iso).
Seeding is done by running the BT client on that torrent when you already
have the full file. Here is the big problem, because the software isn't
quite up to conveniently seeding a large number of files. This is
something that needs to be done, /etc/init.d/bt{seeding,tracker}
{start,stop,reload,restart) with configfiles for what files to seed and
so.
> > I don't think it would be too hard to get a group to mirror the debian
> > CD images with bittorrent to their servers and leave the clients
> > running for the first weak or so till the big rush is over. If Debian
> > says they will only do jidgo and bittorrent the first week that should
> > give enough incentive.
We've said this before and it didn't work then. :) For once I'd like to
get the cdimages out in numbers even for those that want to use http
instead of some strange new software.
> mirrors are based on the concept of really long lasting presence.. i.e
> more than just a week or so. as a mirror i'm happy to contribute to this
> new fangled 'bittorrent' system but so far there has been close to zero
> documentation or examples i can find that allows me to use it in a 'server'
> context as opposed to just a client.
The servers here would be "seeds" in BT terminology. They have the initial
data and makes sure that new clients can get all the data even if there
are no other users currently in the bittorent cloud of users. So basically
for bittorrent there would be use for a couple of servers/seeds but not in
as great numbers as the ftp/http/rsync mirrors because of the P2P nature
of the clients (they'll download missing pieces from eachother).
/Mattias Wadenstein
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