285 'Active' torrents: Is this right?

[Surferosa]

I want to check whether all my utorrent settings are setup optimally for upload speed. The principle is use is on a private music tracker where I would ideally like to seed a large number of small torrents (100-500mb). I am currently running through a Linux box (Debian etch 4.0) via Wine 1.0 and Utorrent 1.8.1. The server sits on a dedicated 100Mbps leased line, has Dual E2180 proc & 2gb ram.

I am aware that I physically wont be able to seed >100 torrents (as per the max. number of active torrents setting- which I have taken from suggested changes to speed guide).

Currently, I have 285 torrents showing as 'Active'. When I initially start utorrent, obviously only 100 seed straight away; and then becuase of the large number that are below 1kBps, gradually the rest move from Queued to Seed (as per the queue.dont_count_sl_upload in advanced). In the unlikely event that 100 torrents were leeched at the same time above this threshold, my understanding is that other torrents would move back to queued status.

With these settings and this number of torrents, typically around 5-10 are seeding at any one time. However I have noticed a large number that connect at a low speed (<1kBps) then drop out almost instantly.

So my questions are this;

1) Is my understanding correct regarding queue behaviour?

2) Will have a large number of torrents being seeded (given the 100mbps line I have) reduce the efficiency of the uploads that are actually occurring? (ie even though they are effectively 'inactive' per the queue.dont_count- will they still be hogging a large volume of bandwidth away from the 'real' active seeds)

3) If it does impact the real 'actives'; how do I find out what the optimal number of seeds to have running is? (or is this pretty unlimited- ie could I have 2000 torrents running if I wanted to- providing I stick with the 100 'actives' setting)

3) Is the behaviour of the leechers dropping out without ever going above 1kBps standard (ie are they just connecting to peers that are closer / quicker to them?)

4) Are my settings most effective for what Im trying to do (which is basically running a ratio building seedbox)?

Really hoping a guru will come along and make sure that Ive set this up the way it should be done.

Cheers.

Utorrent Settings

Connection

Bandwidth

Bittorrent

Queueing

Advanced

[Switeck]

1)Yes, your understanding and observation of queue (seeding) behavior seems correct.

2)There is a slight loss of bandwidth for EACH connection you have, so yes...but given your conditions I doubt they're using more than 100 KB/sec for all your connections to stay connected. For you, that's almost trivial. For me, with only ~2 megabits/sec upload bandwidth...that's about HALF my total upload capacity! (And mine's bigger than most!)

3)In uTorrent's Logger window, you'll probably see connections attempting then immediately disconnecting because they're actually seeds. With enough of them doing that all the time, you'd still register possibly 0.1 to 2 KB/sec on each torrent.

4)Hard to say without knowing more about the torrents "popularity" themselves. If almost every torrent you're on is already seed-heavy, and there's very few peers...your goal to get the most bits out ratio-wise would be reached 'best' by running stupid numbers of seeding torrents at once in the hopes that a new peer downloads from you. Private torrents/private websites with enforced ratios almost break the BitTorrent protocol.

The 100 megabits/second upload setting in my "Suggested changes for Speed Guide" post makes a lot of assumptions that I probably should clarify.

40 upload slots per torrent for every torrent is impractical even if you only have 30 active torrents, resulting in every peer connection being given an upload slot since total upload slots (30 x 40 = 1200) is actually greater than max global connections (1000). So I am assuming the majority of torrents will have very few if any peers to upload to, such as 0-5.

By the same logic, the max connections per torrent obviously can only be nearly reached by extremely few torrents or once again global connection max is exceeded. Presumably, the torrents with the most connections would be downloading torrents that are connecting both to seeds and peers. Were there a separate max connections limit for seeding torrents, I'd have it set to 20.

Even if 100 torrents were seeding at once, using all 1000 connections to do so (10 connections per torrent), the average upload speed PER connection would be ~11 KB/sec. So the numbers still "work" even if they aren't optimal for every situation.

[Surferosa]

Thats excellent- thanks for taking the time to reply: my knowledge of bittorrent in gerenal has improved 10 fold since I found these forums- it has been a huge help.

The scenario you suggest in 4 is correct:

If almost every torrent you're on is already seed-heavy, and there's very few peers...your goal to get the most bits out ratio-wise would be reached 'best' by running stupid numbers of seeding torrents at once in the hopes that a new peer downloads from you.)

Of the c.300 torrents I have running- I have managed to hit a 2 ratio on around 40 of them- and 75 only ratio 1. A large majority of them have no (leeching) peers at any time: but equally a large number have very few connectable seeds (<15). When something does get leeched, given the average file is c.100mb- its not for very long.

The only exception to this is that Ill tend to download and seed maybe 1 torrent per day on average where the swarm hits an equal leech / seed ratio; on these Im finding that speeds will often hit 500kBps and beyond- even if only for a short term period.

So yes, seeding a large number in the hope that I can keep a small number ticking over every now and then is exactly what Im trying to do: I think the most torrents I have seen going at any point is around 15 (usually around 5). Of the c.20gb Im seeding at present- Im running around 1gb a day uploaded- so I guess in those torrent conditions, I shouldnt be too dissatisfied.

The only thing my knowledge still seems a little fuzzy on is whether you should enforce a maximum number of actual seeded torrents- even with queueing.

I read elsewhere comments where you made the point that using Bittorrent for this type of file sharing behaviour isnt really what the protocol is designed to do (ie its designed to hit optimal swarm speeds rather than seeding a large volume of low seeded / leeched files). However, the tracker I am on is a torrent tracker- so torrent it is.

You said;

There is a slight loss of bandwidth for EACH connection you have, so yes...but given your conditions I doubt they're using more than 100 KB/sec for all your connections to stay connected. For you, that's almost trivial. For me, with only ~2 megabits/sec upload bandwidth...that's about HALF my total upload capacity!

So can I assume that there is a ratio that could de derived for upload connection / number of torrents (ie with my connection, could I assume say 1000 torrents max?, whereas a 2mps would be 20?) Or is it simply that it comes down to the 1000 torrent connections that you refer to?

As I said- Im probably still missing something here- I guess what I would like to know whether I can keep on adding torrents to infinity; because eventually global connections or some other will evenually lead to some of them being 'queued' (even when they fall below the slow threshold); or whether I should be self regulating how many I keep.

Thanks for your help once again.

[Switeck]

Too many parts in networking hardware and software are likely to become a bottleneck if you push global max connections past 1000, so that becomes a MAJOR limiting factor!

The connection churn caused by retrying all the ips on every torrent adds up too.

"Yep, this ip is still a seed...after trying it 30 times in 1 hour."

Retrying ips faster (high net.max_halfopen) is only remotely likely to find peers any faster. Better to let them find you! (This is why it's good to not be firewalled in uTorrent...otherwise, they couldn't connect to you.)

I'd say the max number of available-but-idle torrents that you could effectively run with 100 megabits/second is probably in the 1000's...and equally pointless.

What you want to discover is how many active torrents you need to max out your connection's upload. My estimates on that are: 50 reasonably busy torrents (with ~5 peers each) would easily max out your connection. 100 barely busy probably would.

To reach enough active torrents to max your connection...that's going to take lots of testing. And it will certainly vary from hour to hour, day to day. Evenings and weekends (for Europe and USA) likely being busiest...despite ISPs throttling the hardest then.

[Surferosa]

Cheers- funnily enough the site Im on is now in the middle of a freeleech weekend; I have an RSS feed set up on it and its running between 1.0 - 2.5 mBps Uload with 812 'active' torrents on at the moment (with around 50 being actually Active at any one time).

I suppose you could say its not optimal because I should be hitting 12.5 mBps- but, to be honest- with the number I have running (and given the swarm size stays reasonably low.. ie less than 20 seeders & leechers.. Im happy with that).

Thanks for your help- and if anyone else finds / reads this thread, check out links 1&2 from Switeck's signature- invaluable.

[Switeck]

There must be LOTS of people on those torrents either with slow lines, bad BitTorrent settings, or already getting their download and/or upload maxed out from other peers/seeds.