Download succes, but file corrupt

[hugbug]

If quick check reports file is OK but full check finds a lot of bad blocks this means the downloaded data were not written correctly into disk. This is most likely a hardware issue. RPi is known for issues if power supply isn't perfect or the cooling isn't good enough.

If you don't remember how NZBGet was installed, then for a test install it into a separate directory using installer from download page. Try how it works with this version. You can delete it later easily.

[ryan]

Power supply issue is certainly possible - I think it's getting on for 2 years old now, although it wasn't used for it's first year and rarely hits it's supply limit.
It does have cooling but is in a warm place, idles around 48C.

It just seems suspect that it only happens on these large mkv downloads, and doesn't happen on the smaller multi-part rar splits of the mkv files - I rarely see anything needing a repair there and they all play as they should.

I'll try to install a seperate instance of NZBGet and see how that goes - will try both the 21.0 stable, and seperately try the testing release.

[ryan]

I finally got round to installing a seperate copy of nzbget - the latest, 21.1.
I set it up manually, didn't import previous settings, but configured it similarly.

This is the par fail lines from the log:

Code: Select all

File Movie.mkv has 4177 bad block(s) of total 4912 block(s)
Need more 4176 par-block(s) for Movie
Repair failed for Movie: not enough par-blocks, 4176 block(s) needed, but 491 block(s) available.

In a short while I'll try the same download on my PC, but I suspect it will download correctly.
I'll also try SabNZBD+ too to see if it's totally Pi related, or nzbget.
As I've said before, I only get the issue on large mkv releases that aren't split into multi-part files and are released as just the mkv with par2 files.
It's very rare that I get a fail on a multi-part rar download, and I've never had corruption after download other than the usual articles missing at the point of download.

[ryan]

So, a little more download testing.

Using:
NZBGet 21.1 - new install - raspberry pi - Broken download - download completes, quick par check is okay, full par check fails and file doesn't play
NZBGet 21.1 - updated old install - Raspberry Pi - Broken download - download completes, quick par check is okay, full par check fails and file doesn't play
Sabnzbd+ - new install (for testing) - raspberry pi - download completes, file verifies, file plays fine.
NZBGet 21.1 - updated old isntall - Windows 10 PC - download completes, file verifies, file plays fine.

So the Pi is capabable of downloading that file successfully, but it seems that it's something to do with how NZBGet is doing the directwrite on the Pi that's failing to write successfully?
Is there any other tests I can do to identify the issue? I have a 15a 5V power supply (for LED strips) that I can wire to the 5v pins of the Pi to Power it to rule out the power supply, and I have a powered external drive I can try downloading to to rule out the existing drive.

[hugbug]

SAB is not multithreaded and probably produced less load on the system (and lower download speed). Less load means less power drain, less heat, less chances for hardware issues to appear.

As for DirectWrite, you can disable it in settings for a test.

"quick par check is okay, full par check fails" means the files were downloaded OK but written incorrectly.

[ryan]

Fair point with Sab vs Nzbget - sab averaged 23.8 MB/s whereas NZBGet usually hits 30 MB/s, so SAB is definitely not hitting the mark. It's so rubbish to work with too.

I've just downloaded with NZBGet with DirectWrite disabled, and it downloaded and had only 4 blocks requiring repair, so was repaired successfully.

I've not yet tried the alternative power supply or disk (HDD/SSD) so I'll try that later this week with DirectWrite enabled too.

[ryan]

Just a bit of an update on this - sort of solved for me.

Took a while, but I got slightly different hardware.
I bought a powered USB hub - previously the HDD was just powered form the Pi, so I guess the Pi wasn't providing enough power.
I've also bought a 240gb SSD, which is used for the OS (and NZBGet's folders) - I have that connected as well as the existing external HDD for storage.

The non-compressed/non-split full-size mkv downloads are fine now - have downloaded several over the last few months and they've all completed successfully and played fine.
I do now have an issue where the downloads slow down after a certain amount (not pinpointed how much exactly yet) - but that's probably a bottleneck I've introduced.