unable to finish torrents, files corrupted after download

[zelwa]

Hi! I am using transmission 2.01 (10898) on ubuntu server (just daemon + WebUI). I have two (possibly) connected issues:

1) Very often torrents are corrupted after download (detected by CRC failed). Every time I could simply corrected it by "Verify Local Data" (and then redownloading some small corruprted part). But it seems to me very strange, transmission should verify hash of every downloaded piece - or am I wrong?

2) Transmission has often problem to finish downloading torrent - just before end (usually 99.9x%) it repeatedly jumps back about one percent or less and redownloading again and again and again... If I use "Verify Local Data" it jumps back a bit more but then finishes downloading without problem.

Both these problems are quite annoying. I cannot try newest version because some trackers does not allow it yet. Any advice? I am only one with such a problems (in forums similar troubles was reported only for much older versions) ?

my settings.json:

Code: Select all

{
    "blocklist-enabled": true,
    "download-dir": "\/data\/torrent",
    "speed-limit-down": 2000,
    "speed-limit-down-enabled": false,
    "speed-limit-up": 200,
    "speed-limit-up-enabled": true,
    "encryption": 1,
    "open-file-limit": 64,
    "max-peers-global": 200,
    "peer-port": 45723,
    "pex-enabled": true,
    "rpc-authentication-required": false,
    "rpc-password": "xxxxxxxxxxx",
    "rpc-port": 9091,
    "rpc-username": "transmission",
    "rpc-whitelist": "127.0.0.1,192.168.0.92,192.168.0.912",
    "watch-dir-enabled": true,
    "watch-dir": "\/data\/torrent\/_watch"
}

[residue]

I have noticed similar problems. Typically, my downloads finish at 100% and I do not verify the data. The file system reports the same size as was indicated by the torrent. When I was playing back the media, I noticed obvious issues with the file. I check it by using the 'verify local data' feature, and discover pieces are missing. I often find that when the problematic torrent completes there are missing / bad chucks. The data is reported as being 100% available; I keep receiving data that fails checksum.

I found a few issues where people describe similar situations:

https://trac.transmissionbt.com/ticket/1242
https://bugs.launchpad.net/ubuntu/+sour ... bug/217692

I was using stock transmission provided by Ubuntu. I've upgraded from source to 2.12 and continue to have this issue. I'm not sure whether it is a problem with the client, or if it's just bad trackers / bad peers.

However, the client log does report pieces failing checksum test after receiving them. I'm finding it difficult to believe the client is the problem. The client appears to behave as it should. The only part missing is a mandatory check upon completion. Perhaps if transmission were to verify the data and keep trying, users might not notice this as a 'problem'. However, there is a nice 'run a script upon completion' feature, where one could run a script to verify their downloads and try again only if the data failed checksum.

[Rolcol]

Even with bad peers, the data should be rejected, and that appears to be working since the messages are showing up in your log. The only data that should be written to the fully checked piece. I'm not aware of any bugs that affected 2.12, so is it possible that the issue is external? Do any other programs modify the torrent files in any way that could cause the issue? Perhaps there's a physical issue with your hard drive?

[lakrigg]

Check no indexing services are running on the DIR

Check network card MTU as well as your modems MTU
ifconfig , will tell you this.


If you have MTU issues this can cause file corruption and skipping of missing elements of files ect.
Perform a tracepath to each of your hops discovered by a traceroute to ensure MTU isnt out.
Check Lan cable.

Are you running a SMB share on this DIR? or another PC accessing it? If so try and stop smb/cifs for testing.
Torrent with very high speed can sometimes cause issues on certain setups, if you cap the speed lower do you notice improvement?
I beleive torrent app's throw out trash data for discarding, perhaps it could be an issue with your version or something associated with it.
I hope its not a USB drive

good luck


It could be ram or HDD, but seems a bit odd if its only torrents.

[residue]

I believe I found a solution to what my problem was:

I recently setup a raid-1 and was downloading torrent content to that drive. When I downloaded the same content to my main disk, non raid-1, the torrent completes fine; verifies local data fine; no bad sections are reported.

From now on, I suppose I'll just download to my non-raid drive first. When I'm done I'll copy it to where ever I want.

I'm not sure if this is behaviour I should have expected from a software raid-1 (mdadm), but I won't be saving any content to the drive until it's complete.

Not sure if this helps anyone else, but thought I would at least point out what worked for me.

EDIT:
I finally decided to test my memory. I removed every module and ran memtest86+ for every individual module. I eventually came a cross the culprit: I couldn't even get past bios with one of my bad memory modules. Removing the bad module did the trick. I'm not sure why I had not run into any data corruption problem before.

The easiest thing to verify the RAM was the cause of the issue was generating sha256 checksums from my 'GOOD' hard drive, copy the files over to the other hard drive an run sha256sum -c SUMS_FILE. Everything seems great. Now, running transmission and saving media directly to my newer hard drive works just as expected: no more constantly stuck at 99%.