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Seeder indicates less then 100% availability


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Posted

I'm watching very slow torrent (actually one in lot of 8 offered by the same source).

Accordingly to "Main Page | Seeds" column I always see: 0(1). Meaning, there is 1 seeder, but it's not connected to my client. It's not correct. Time to time I'm getting connections from the seeder, because:

1. the host never takes a byte from my client - it only downloads to my computer, and never sends requests to upload anything from it. And during the last week of watching it has downloaded a lot...

2. the host always participates in all torrents in the batch, provided by the same source;

3. the host always indicates 0..1 - 0.2% "Availability" and, at the same time, it usually shows 0.2 - 0.4% "Relevance". Note: "Relevance" is bigger then reported "Availability".

4. torrent has about 5 - 8 peers. Because it's very slow - the community changes very slowly as well. During that time I have never formally seen connection from a host with 100% availability (seeder) and, as I've said, the "Seeds" column always indicates 0(1).. You may agree with me - it's not a common case at all.

The problem I see is:

1) why seeder doesn't reveal 100% availability of content? Instead it shows availability around 0.1 - 0.2%, while during the run the "Downloaded" column indicates that it has downloaded a lot (hundred MiB of data).

2) I think "Relevance" column should never indicate % bigger then "Available" % column does. There is something wrong otherwise...

3) due to reporting low "Relevance" % to my client - I'm getting a lot (tens) of incomplete pieces sitting in "Pieces" box and indicating 0 "Availability". I guess they will be resolved later, but meantime it looks weird (see my post - http://forum.utorrent.com/viewtopic.php?id=62770 ). I think it's related to the fact that the seeder "fakes" (or somehow "manipulates" with) availability.

I'm using uTorrent v.1.8.4

Seeder indicates client uTorrent v.1.8.3.

Posted

I think I know why and how it happens.

Seeder time to time makes connection and, instead of offering all available pieces, it offers a random and very limited subset of available pieces. After a while it disconnects, not finishing some of them. Next time it connects - it offers yet another limited subset of pieces to download.

That's exactly what I see. uTorrent accumulates a big number of pieces that become unavailable and just cached. I don't think that they even available to further upload from my client to others... It's a bad, temporary useless ballast, because:

1. I can't use it - files are uncompleted.

2. I can't unload it to other torrent clients (peers).

3. it makes a mess in statistics (my "Downloaded %" is noticeably, more then several percents, bigger then "Availability" for the whole torrent).

If it's not a bug, but a feature, how can I get up-front indication that particular torrent in fact uses it, so I can drop this torrent altogether and better use another one offering the same content, but without "superseeding"?

I don't want to waste a week before coming to conclusion that torrent uses "superseeding". An up-front indication would be helpful in this case.

Posted

More pieces get out faster? What I see is just exactly an opposite.

My uTorrent has downloaded a lot of uncompleted pieces and that data can't be shared (uploaded from my computer to other peers), unless it gets completed here. I presume that other peers have the very same problem. They collect data that can't be shared with my computer the same way.

It, among other things, slows down spreading out torrent content between peers.

Posted

If you have read my initial post I was talking about a lot of uncompleted pieces, collected on my side. The key word here is "uncompleted", not a "unique" pieces. Peers can't share uncompleted pieces, or can they?

Posted

Yes, that exactly what I want to do. If there is another torrent offering the same content and it's not configured to use "superseeding" feature - I'd like to switch to that torrent immediately. And I'd suggest others to do the same.

To see the picture a bit more clear - let's make this assumption. Let's assume we have 1 seeder and 5 leechers. In worst case all 5 peers take form seeder all pieces and accidentally all of them are uncompleted. To make it happen seeder will have to upload almost x5 times more then torrent's content (taking 5 times more time). All peers will indicate 0% availability while keeping almost 100% of the date (actually if piece contains 255 blocks, it'd be (255/256)*100%). At this time they can't share with each other all blocks which they have collected and all of them just wait for the one last block for every piece in order to be able to start its upload to other peers.

Sure, it's an extreme case with probability it happens in real life close to 0, but it's possible nevertheless. And it indicates that torrents with superseeding spread its data more slowly, then they should. It's because of the locked pieces (which can't be shared among peers, until completed) the seeder statistically have to upload more data then it could (in best case - just 100% of data, that will be shared among peers by themselves).

Posted

The thing is, your theoretical scenario does NOT happen at all in superseed scenarios in the real world. the seed remembers which pieces went out to which peers and doesn't try to duplicate them. Also, unless there are connection issues, it doesn't cut off peers from finishing pieces. Your solution isn't really a solution to the problem.

Posted

Presume that you're right and seed remembers what pieces it has downloaded to me and left uncompleted - why, the next time it connects, it doesn't finish those pieces? My computer showed me 80+ of them at a time... And all of them show "Availability" '0', while the seed is connected ! I guess the answer is - even if it'd have an intention to complete those unfinished pieces - it can't for some reason (one of them could be - it simply doesn't remember)...

There is no connection problem between the seed and my computer. Time to time it connects, makes upload, sits without any activity, uploads more, sits again, disconnects (timing and actions are random)... Then the circle repeats again. Everything is as usual. I do not see that disconnection makes the problem, the algorithm itself - does (or there is a bug).

I clearly see that the seed does cut off peers (me) from finishing pieces and it doesn't want to resume those pieces again when it connects next time .

Posted

It's uTorrent v.1.8.3 (at least as I see it). I've mentioned it in my first post.

My client is uTorrent v.1.8.4.

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