Is Verifying Data Required? - Magnet Links

[cgimusic]

Every time I pause and resume a download that was started with a magnet link Transmission insists on verifying all data. This is a major inconvenience as it takes several minutes to verify even a small torrent. Is verifying the data technically necessary, part of the magnet scheme or just a bug. Can it be turned off?

Thanks in advance.

[WLS]

Just my thought. I could be wrong.

By verifying data, Transmission knows where to start downloading packets that you don't have for that torrent.

[Spadge]

My guess would be that transmission needs to verify data every time because it stores resume info in a file named for the .torrent file hash.

Which magnet links don't have, right?

That'd be my guess.

[cgimusic]

After looking into it further it only seems to happen the first time you pause and resume the magnetized transfer.

Not quite as annoying but still strange. Might as well just download a few kilobytes of data and then pause and resume so it doesn't try to verify huge amounts of data later.

P.S.
This is easily replicated on all my machines. I assume this is a bug as I see no technical need to verify magnet link data after the first pause and resume. Should I submit a bug report or does anyone have another explanation?

[Spadge]

Out of interest, watch the logfile (tail -f) as you add a magnet link and see what it does. Then pause it and watch to see if it then, and only then, writes a resume file.

If it's only able to get the torrent hash after it's started the download (torrent files have that stuff written in them), and only saves a resume once it's basically told to, then this is behaviour that transmission needs to change if it's to properly support magnet URIs.

Thanks

[cgimusic]

As far as I can tell the resume file is created as soon as the torrents meta-data is downloaded. It will also create it sooner if you pause a download before it has the meta-data.

If it does create a fully valid resume file then why isn't Transmission using it the first time you resume a magnetized transfer?

[Spadge]

If it does create a fully valid resume file then why isn't Transmission using it the first time you resume a magnetized transfer?

I'd say that's your bug right there then

[cgimusic]

Thanks guys. I just added a Trac Ticket.

[Rolcol]

Adding an actual .torrent requires the data to be verified before the torrent is even started. Transmission needs to verify the information that is there and it only does so after all the metadata is downloaded in a magnet link. It's a bad method that could be improved.