Exploiting Networks

[martix]

So today I came up with this idea to exploit my little two-computer home network I have. Now both of them have all their drives mapped, so everything is shared. Say I start a torrent on one of them, then start the same torrent on the other one and put them in the same location? What would happen?

If they actually work in coordination, that would mean double the speed - which would be veeery nice... Do they? If not I want that feature in. I mean - its too good to pass up.

[DreadWingKnight]

They would puke all over each other.

Local peer discovery and using things that way would work better, but ONLY if the two machines were accessing separate internet connections.

[martix]

Thats the whole idea - taking advantage of both connections. They are all completely seperate.

So how would I do that without having to download the torrent 2 times - one for each client.

[DreadWingKnight]

You can't.

You can only use LPD or manually add your other local to make sure that the two clients are syncronized.

[robincheema]

thats sad...

[Lord Alderaan]

Split the torrent up or something. It has been discussed before. The fact this is difficult isn't just a µtorrent thing.

But in the end its just best to download different torrents on each computer instead of trying to force 1 torrent over two machines.

[funchords]

You can do exactly what the O.P. suggests with Azureus, but it really doesn't help with speed in the way that most would think. The instructions are in their Wiki. The need for this is rare.

Essentially, Azureus uses a feature that walks through each piece of a torrent on an ongoing and consecutive basis to see if any of the data that was recorded there before has been updated and now passes the hash. If it does, then the piece is marked as "HAVE" and is made available to the swarm.

That way you can have multiple swarms, even multiple clients on different machines, contributing to the same file.

From experience, though, if the torrent has too many pieces, Azureus can't keep up and some waste is introduced. (Harmless but excess data that gets downloaded and discarded.)

Here is where it comes in useful:

1. File XXXXXYYYYYZZZZ.ZIP is on Private Tracker ABC and Public Tracker DEFG. Although the file is identical in both swarms, the hashes are different as one has the Private Flag set and the other does not. Because the initial seeder has a small upload pipe, neither swarm is being fed very well at all.

2. You can connect to both swarms, making the download location the same for both files. (Other adjustments are needed to prevent exclusive locking and to turn on the piece checking that I described. These are covered in the Azureus Wiki.)

3. Once working, your computer makes available unique pieces that were previously only available to one swarm. The private swarm is still privacy-protected. The only thing being shared between both swarms is the file data.

On a separate note: If you simply want to double the speed (assuming the swarm has the speed out there to double), then double your upload limit and double the number of upload slots. If there are more good peers out there, then the protocol will find them (give it about 15 minutes or so, usually less).

[system]

If you can get both machines to see each other with LPD, try starting the torrent on both. There will be data that both download, but there should be a lot of data shared between them at the speed of your LAN as well. Should finish up with 2 copies faster than you would get a single copy.

[Lord Alderaan]

Essentially, Azureus uses a feature that walks through each piece of a torrent on an ongoing and consecutive basis to see if any of the data that was recorded there before has been updated and now passes the hash. If it does, then the piece is marked as "HAVE" and is made available to the swarm.

Wow I and though it was just the java thing that caused Azu to use unjustified amounts of system resources. [edit]Ah ok wait this is a optional feature of course. Well seeing as Azu allready uses quite some system resources this isn't going to make it better[/edit]

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@system: Good point. With LPD you could download the same torrent with two clients and hopefully they'll exchange data at full speed. But both would still have to download to a different location (you'd need double the space). Because two µtorrents writing and reading (especially with the caching and all) to the same files could and probably will cause weird behavior. It still would be even better to just download different torrents on each machine because even with LPD and two different locations there is gonna waste.

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@funchords: He probably has his upload maxed on both machines. He said in his 2nd post each computer is utilizing a separate internet connection. One machine/utorrent cannot utilize two internet connections decently/optimally so his setup is the best for a dual internet connection (imho for bittorrent traffic this is preferred even to a dual-wan load-balancing router).