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Impact on Trackers

Automatic cross-seeding is a relatively new practice, and while it brings some benefits for trackers, it also has some drawbacks. In this doc, we will outline the benefits and drawbacks, then discuss strategies you can use to minimize cross-seed's footprint.

Benefits​

The benefits a tracker sees from automatic cross-seeding largely center around retention. Having more seeders leads to healthier swarms, longer retention, and fewer dead torrents.

It is particularly helpful for new trackers looking to build a catalog—often, backfill uploads are not particularly well-seeded because the users have already downloaded them from elsewhere. But any cross-seed users will automatically pick up the new releases and reliably seed them, increasing redundancy.

Drawbacks​

Private BitTorrent trackers are small-budget hobby software projects that run on donations and the good will of the sysop. They do not run on infrastructure like Google's or Amazon's, and they cannot support infinite load.

Automatic cross-seeding causes more load on trackers than any previous form of automation (e.g. Sonarr). We, and the tracker administrators we've spoken to, believe the benefits outweigh the drawbacks. However, not all trackers hold the same opinions, and we haven't spoken to all of them.

What is "load"?

We can break load into 3 distinct actions that cross-seed (and all other tracker automation) performs:

RSS requests​

  • cross-seed initiates an RSS request by searching with an empty query. These are usually cached and updated regularly, so the tracker's server is sending you a precomputed file.
  • These are cheap in both compute and network I/O, so we generally don't worry about them.

Search requests​

  • cross-seed searches for movie and TV show names individually.
  • The tracker's server has to scan through its catalog looking for releases with similar names.
  • These are expensive in compute, but cheap in network I/O.

Snatches​

  • cross-seed will snatch any torrent that has the same release group, source, resolution, and rough size as your owned torrent.
  • The tracker's server has to add your passkey to its stored copy of the torrent file, then send it to you (and it's often quite big—a few megabytes).
  • These are expensive in network I/O (and maybe memory), but cheap in compute.
  • Some trackers count snatches for their user rank systems, and snatching many unnecessary torrents may be seen as abuse.

How cross-seed's Default Settings Minimize Load on Trackers​

As of version 6, cross-seed's default configuration aims to minimize load by being selective about which torrents it searches, and by working through its backlog slowly. See the latest default config file.

Skipping episodes​

It's usually not worth it to bother cross-seeding episodes since they will be deleted in the near future (when season packs come out). By default, cross-seed skips episode torrents.

If you are racing or never download season packs, and would like to turn on episode searches, set includeSingleEpisodes to true.

caution

There are TV shows that are not combined into season packs, such as game shows, talk shows, and similar. These shows are known as dailies and often have naming which specifies dates, rather than SeasonEpisode (S02E03) style. Searching with includeSingleEpisodes and using risky on these torrents, or files, can result in many torrent files being downloaded for comparisons for matching only one individual episode.

Remember, this would occur on just one (torrent) search, within the entire (all data) search.

Skipping torrents with unknown/extra files​

Torrents that are "purely" video files are the most likely to find matches. By default, cross-seed restricts searches to just these torrents.

This excludes anything that is not movie or TV content, but will also exclude anything that contains .nfo, .srt, .txt or other non-video files, even if the primary file is a video file. This is restrictive, but it works well with matchMode: "safe" because it only allows the torrents most likely to find perfect matches.

If you enable Partial Matching, you should set includeNonVideos to true because the partial matching algorithm can handle the extra files.

Backlog searching 400 items per day​

By default, cross-seed only searches 400 items from your backlog per day. We do this for a few reasons:

  • If you have a high excludeRecentSearch of one year for example, intending to do a rolling daily search of the torrents that were last searched a year ago, torrent searches will "bunch up" once a year (depending on when you first set up cross-seed) to be searched back to back, potentially causing rate limiting problems for your other automations due to the high search volume (Sonarr, Radarr, etc.).
  • Long-lived bulk search runs encounter drift - while they run, your other automations will be downloading new torrents, moving data files around, and deleting torrents and/or data files, and the snapshot cross-seed took of your torrents at the beginning of the search goes out of date. Keeping bulk search runs short helps a lot.

You may have an instant gratification mindset, and we get it! Seeing your total number of cross-seeds and your final seed size on a tracker is exciting. With that said, please try to balance that mindset with being friendly to your trackers.

The important thing is that you seed for a long time - not that you start seeding as early as possible.

This is configurable with searchLimit.

Preventing Repetitive Searches​

cross-seed caches the snatches it makes, but does not cache search results as they can change over time.

For this reason, cross-seed enforces that you have configured the excludeRecentSearch and excludeOlder options, and its defaults are set such that cross-seed will search for things recently downloaded a few times, but only search once for things downloaded far in the past. These settings will build your backlog of cross-seeds, and sufficiently catch new releases trickling to other trackers.

Pausing between searches​

As of version 6, cross-seed enforces a minimum 30 second pause between individual searches during any bulk search. This only applies to bulk searches, not webhook-triggered searches.