SABnzbd Forums

@SigHunter:

Did you use my git version, so from https://github.com/sanderjo/sabnzbd.git, which has automagic -N detecition & usage ? Or did you use the official SABnzbd git version?

And: thank you for bringing this up with your "However I can without any problem (always!) repair it with par2repair -N *.par2 *" in your opening post.

i successfully ran the commands you posted, thus using the version from the par2optionN-branch

I asked the par2cmdline dev why this -N was introduced:
https://github.com/Parchive/par2cmdline/issues/65

Basically because the way it used to search (or when you turn on -N) can cause in rare cases and infinite detection loop, causing the repair to run for ages, he calls it a sort of DDOS.
Windows/OSX use par2tbb, which is vulnerable for this bug, but we never got any reports about that, so probably safe to assume for usenet posts don't have any problems.

Iasked the par2cmdline dev why this -N was introduced:
https://github.com/Parchive/par2cmdline/issues/65

Ah, great. Thank you. And great that the maintainer has reacted. I've uploaded an example problematic set.

Basically because the way it used to search (or when you turn on -N) can cause in rare cases and infinite detection loop, causing the repair to run for ages, he calls it a sort of DDOS.
Windows/OSX use par2tbb, which is vulnerable for this bug, but we never got any reports about that, so probably safe to assume for usenet posts don't have any problems.

What is your exact assumption? That "-N" has been implemented already in par2tbb, as an always-on feature?

What is your exact assumption? That "-N" has been implemented already in par2tbb, as an alway-on option?

No, the -N is the 'old' behavior, the way it was implemented before par2cmdline 0.6 and thus also the way it is in par2tbb (since that's just par2cmdline 0.4).
Only when they discovered this 'DDOS/collision-bug' recently they disabled the old block-search behavior to avoid the bug in par2cmdline 0.6+.

safihre wrote:

What is your exact assumption? That "-N" has been implemented already in par2tbb, as an alway-on option?

No, the -N is the 'old' behavior, the way it was implemented before par2cmdline 0.6 and thus also the way it is in par2tbb (since that's just par2cmdline 0.4).
Only when they discovered this 'DDOS/collision-bug' recently they disabled the old block-search behavior to avoid the bug in par2cmdline 0.6+.

Oh ... wow ...

So introducing it again in SABnzbd could be dangerous?

Let's wait for the author's response on the specific example on github.

We have had reports of hanging par2 repairs on Windows.
Advice was always: turn off multithreading in Config->Switches.
The cause may have been the bugs associated with -N

OK, so...I'm running SAB on Ubuntu 15.10 ...
..often get this "not enough repair block" error...
...same data are easily repaired by quickpar running through Wine...
SO..
How should I configure SAB to make it works?
Thanks for your help

Did you try what was discussed here?
Use Beta6, install a recent par2cmdline and set the -N parameter.

I'm not English native speaker...so hard to decode everything in this thread...
I uses releases provided with ubuntu, where do I find Beta6?

moreje wrote:I'm not English native speaker...so hard to decode everything in this thread...
I uses releases provided with ubuntu, where do I find Beta6?

In the PPA by jcfp. See instruction on http://wiki.sabnzbd.org/install-ubuntu-repo how to use it.