how does DL priority work?

[hexa]

Not quiet big enough a problem to call for troubleshooting.

I have a .torrent file which consists of more than 700 components. Of those I chose some 30, which included quiet some searching. I set all of them to low priority and only the top 4 ones to high. There are 4 seeds and about 50 peers around. Still I'm getting hardly any blocks from the priority files. The percentage of all files is almost equal doesn't matter the priority. In a sense I'm a bit worried that I in the end have nothing complete at all should the torrent vanish.

Can someone explain to me how the priority really works, or why it fails sometimes?

[Ultima]

Because BitTorrent isn't a traditional file transferring protocol. What you want, you don't always get because other people aren't always sharing what you want.

[hexa]

ok, I understand that. but i thought that a seed has the complete data set available. assuming i'm d/l with a decent speed from a seed i should get the blocks i'm looking for, not? i mean i get them every now and then, and these blocks have a high availability anyway and d/l very fast. from this one guy i just get more blocks i'm not yet looking for, and every now and then even some i designated 'skip'.

[Ultima]

That depends on the seed, and whether it honors your request, or instead looks out for the interest of the swarm (yes, piece/file prioritization screws up piece distribution, harming the swarm). Super-seeds, for example, fit into that category -- they try to decide what pieces peers get so that the torrent contents get spread as much as possible.