Hello,
-KTorrent 4.0.4, Ubuntu 10.10.
-I want to understand what the DATA check is doing.
-Since: I am noticing a lot of torrent downloads have 'failed' blocks (probably not KTorrents fault).
-I set Settings->ConfigureKTorrent->Check DATA when download finished.
-I notice some torrents are rechecked and download continued more than 10 times until I stop them (and failed blocks remain-often at the >97% level).
-(From other posts, but issue still remains) I unchecked Settings->ConfigureKTorrent->QueueManager->Keep seeding after download finished.
and max connection setups=10.
-If I turn off the DATA checking when finished. For files with .rar. They often unrar fine. For torrents including a single video file I can't see any distortion in video quality even though for both these cases a manual data check shows failed blocks.
-The only thing I can think of that is causing the issue:
i.) There are bad chunks in the swarm that and continually seeding this section of data in my download?
kind regards,
Ian.

The data check loads each chunk and checks if it matches with the SHA1 hash of that chunk specified in the torrent file. The chunks are also checked when they are first downloaded, so seeing that you get to the end of the download, the download must be going fine.

On what kind of filesystem are you downloading ?

-Interesting. Assuming the torrent is good, your saying if the data is saved to the hard disk, i'm receiving the correct data?
-I have about 15 torrents >98% at the moment with failed chunks. NOTE: Some torrents get corrected on continued download after a data check but these don't.

-My KTorrent is downloading on a Ubuntu 10.10 (Debian) OS with hard disks formatted as Ext4, however default save and completion directories are a network mount '/mnt' of 4 hard drives totalling a 4TB NAS called QNAP (Debian) in raid 1 with hard drives formatted as Ext3.

Folder to save torrent info: /home/jaeger/.kde/share/apps/ktorrent/
Default save location: /mnt/Downloads/Uncompleted/
Move completed downloads to: /mnt/Downloads/Completed/
Copy torr file to: /mnt/Downloads/Torrent_Files/Completed/

Hello,

-IT IS NOT THE HARD DRIVE. Since all programs except KTorrent, believe the data is fine.
-uTorrent, examines the downloads as 100% completed with no errors. .rar files extract with no errors.
-Partly based on this forum, I purchased a brand new hard disk and moved the torrents to this and continued the download from >98% on 15 torrents. Subsequently, a data check still shows some failed chunks.
-Some newly started torrent downloads also exhibit this behaviour.

-Until this bug is rectified. I can't work out, how can I seed without KTorrent continually re-downloading from 98%?
-Since private trackers etc also seem to register the download as complete I would like to tell KTorrent to move the torrent to completed mode and seed without download (it doesn't appear possible).

kind regards,
Ian.

Try this, stop all torrents, and then do the data checks.

If it is what I think it is, then the data checks should be OK.

-Stopping all torrents (rebooting) and performing a data check. Some torrents move to completed as the data check reports 'found' some chunks moving the download to 100%.
-Those that have a handful of failed chunks. Several data checks move the file to 100%. (works on files <1.5GB).
-Performing multiple sequential 'data checks' on downloads with 'failed chunks' (more than a handful) (frequently on torrents >4GB ), the sequential data checks report a different number of 'failed blocks' and 'found' each time but do not fix the issue and often state the download is >99% complete.

The checks fail due to continuously hitting the open files limit. You need to increase the maximum number of open files. This problem is already fixed in the latest development code.

-I have been using the following open files limit (I changed the default from 1096):

edit /etc/security/limits.conf
* - nofile 4096

-From your response I have increased to 9046 and rebooted so the settings take affect.

-Stopping all torrent and performing a data check still shows up failed checks.
-My current solution to this issue, is just to turn off 'complete check when file downloaded'. If a download is corrupt then use utorrent for the remaining pieces.