What are the default limits?

[balupton]

For some reason, these are the limits that are set for me:

What do each of them actually mean, and what are the overlaps. If I do 200 for dht, trackers, and lsd and say 500 for active. What happens? Wouldn't active always just be downloads+uploads+checking? What are the recommended values? And how much RAM usage should I expect per hundred torrents?

[qstokkink]

These are low-level settings, documented at https://www.libtorrent.org/reference-Settings.html. I'll quote the relevant part.

If there are too many torrents some of the auto managed ones will be paused until some slots free up. active_downloads and active_seeds controls how many active seeding and downloading torrents the queuing mechanism allows. The target number of active torrents is min(active_downloads + active_seeds, active_limit). active_downloads and active_seeds are upper limits on the number of downloading torrents and seeding torrents respectively. Setting the value to -1 means unlimited.

For example if there are 10 seeding torrents and 10 downloading torrents, and active_downloads is 4 and active_seeds is 4, there will be 4 seeds active and 4 downloading torrents. If the settings are active_downloads = 2 and active_seeds = 4, then there will be 2 downloading torrents and 4 seeding torrents active. Torrents that are not auto managed are not counted against these limits.

active_checking is the limit of number of simultaneous checking torrents.

active_limit is a hard limit on the number of active (auto managed) torrents. This limit also applies to slow torrents.

active_dht_limit is the max number of torrents to announce to the DHT.

active_tracker_limit is the max number of torrents to announce to their trackers.

active_lsd_limit is the max number of torrents to announce to the local network over the local service discovery protocol.

You can have more torrents active, even though they are not announced to the DHT, lsd or their tracker. If some peer knows about you for any reason and tries to connect, it will still be accepted, unless the torrent is paused, which means it won't accept any connections.

So, to answer your questions. "dht, trackers, and lsd" are non-overlapping: the individual mechanisms simply follow these limits. "Wouldn't active always just be downloads+uploads+checking" is about correct, but "active" excludes "checking" torrents (a "check" being local file integrity on your disk). "What are the recommended values? And how much RAM usage should I expect per hundred torrents"; the recommended values are prefilled, but every system is different - like, REALLY different - and you will need trial-and-error to find the best values for you particular system.