Making a torrent properly is one of the most overlooked aspects in torrenting. Most users of
bittorrent only create the .torrent files occasionally, if at all, and others make bad choices
and mistakes, which can antagonise people, or make torrents slow to propagate, and lead to an
early death.
In the past, we’ve covered how
to make a torrent, and possible ways to revitalise a dead torrent.
This time, we’ll cover what steps you can take to keep a torrent as healthy as possible for
as long as possible.
Trackers
A mistake that was common just a few months ago, was throwing out torrents with multiple trackers
listed on it. Until recently, a number of torrents listed on the Pirate Bay, had the same tracker
listed multiple times under different aliases, something they have since corrected.
There are also occasions where up-to a dozen different trackers are listed, all for one torrent.
Some might argue that adding more trackers to a torrent is a good thing, but the fact is,
it’s often harming things. Clients that can only handle one tracker, will only announce to
the first one listed, and ignore any subsequent trackers listed. Multi-tracker capable clients
will announce to the first tracker, as well as any subsequent ones, depending on how they are
grouped. The thing is, every peer on the second tracker, will also have announced to the first
tracker, and would be available there. However, the peers on the first tracker may not be on any
other trackers.
At the end of the day, you’ve gained no new peers (unless the initial tracker was
overloaded or down) but used up connection time and bandwidth on your connection, and more
importantly, you’ve added an extra load to a tracker. While it may not seem a lot, with
even a single thousand-peer torrent, and a 15 minute limit on re-announcing, that’s 4000
extra, needless connections per hour, per torrent.
The solution, use DHT if your client supports it, or if you’re strongly adverse to DHT but feel
there is a possibility that the tracker might go offline, you can use a second fall-back tracker.
Don’t disable DHT for the torrent though (by setting the private flag) because it can help
the torrent die that much faster.
Padding Files
This is a little foible that’s pretty much unique to the BitComet clients. A
padding file is an extra file, comprising junk data that’s added to torrents, so that files
all start at the beginning of a torrent piece. In theory, this means that if you only want
certain files in a torrent, you don’t have to download an extra part, belonging to another
file. It is also supposed to make torrent ‘previews’ easier.
However, you don’t save any data downloaded. What you gain from the front will even out
with the added data needed for the larger padding file needed at the beginning. Worse, if
you’re downloading multiple files, the padding files can add up in size, and examples have been
seen where padding files have been 25% of the total torrent size.
For the average user, there is no good reason to use padding files. The is certainly no reason
that compensates for the added irritation those files give to other users, or the increased data
bulking up the torrent.
Piece Size
Piece size is the bit that can make a torrent seeded on a home connection scale well, or make
even the best seeded torrent bog down. At its heart, it’s how big each piece is that is
checked, and distributed, but also how much data you discard for a hash-fail. Make the pieces too
few and big, and it can be very hard for a peer to get started, too many small pieces will use
more of a peers connection for overhead.
It’s a delicate balance, that is not easily found. Small pieces make it less susceptible to
poisoning attacks (as practiced by MediaDefender, among others) and will help a torrent deal with
sudden increases in peers, by making it easy to get a piece or two to trade. However, keeping
track of who has what piece requires bandwidth, and small pieces mean that you will be telling
connected peers about pieces you have just got more often.
After a number of years toying around, the optimum number of pieces seems to be between 1200 and
2200. Most torrent creators will only allow piece-sizes in multiples of 16kb, so you should, with
few exceptions, find a size that fits in that range. A 700Mb torrent should be 512Kb pieces
(giving 1400 total) and similarly, 350Mb would be better with 256kb. A 4.5Gb torrent would have
2,250 pieces, roughly, with a 2Mb piece-size. Or 1,125 with 4Mb. Either way would be fine, but
256kb pieces would mean 17,500+ pieces, and is too many.
File Layout
The file-layout is something that can be key in determining how long the torrent lasts. The
layout of a torrent and the data in it, is one of the most important factors in torrent
longevity. In general, rars are not encouraged, and can lead to a shorter torrent life. Mainly
this is down to the doubling of space this requires, space for the files, and space for the
torrented rar. The only observed exception to this seems to be ’scene rars’ where the
rar files are widely available from multiple sources.
For multiple file torrents, directory names are also as important as file names. An accurate, and
descriptive directory name frustrates less, than one called “temp” or
“001” which can clash with similar named directories on client computers. It should
also be noted that although most torrent creators will name the torrent file after the parent
directory in the torrent, the torrent file can later be renamed without worry. There is a general
misconception that torrents can only contain a certain number of individual files, which is not
true.
Also, be wary in adding extra files, such as small text files with a hello, or attribution.
Without this exact file the piece can not later be resurrected in a reseed. The more complex the
file, the harder a reconstruction, if someone else wants to reseed. That music video of your band
might be on someone’s hard drive, but if you had a fancy nfo file full of ASCII-art, which
someone has deleted, it not only won’t reseed, but will delete the end of the re-seeders
copy of the video when it is hash-checked.
Connection Settings
Finally, and not directly related to making a torrent, make sure your connection settings are
optimized. We have published hints on optimizing µtorrent
and Azureus/Vuze
in the past, as well as more general guides. Make your torrents right, and they will last longer,
providing you follow one last tip – SEED. Without seeding, any torrent will
die sooner.
Post from: TorrentFreak
aurelie67
VH1
MTV
Recommandations
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and reject those that you are not interested in
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