"Download all par2 files" switch option

[kevindd992002]

How does downloading all par2 files prevent multiple repair runs? And when does a multiple repair run event occur?

In my understanding, SAB only downloads the number of required par2 files to repair a download, right? Won't the default setting (download ONLY required par2 files) be the optimal setting compared to always downloading all?

Not complaining here but I just want to understanding what this setting is for. Thanks.

[safihre]

If after the first scanning by par2 it turns out we need for example 15 extra blocks, it might be that the par2 files will also be damaged. So sabnzbd will download those 15 extra blocks, par2 will run, scanning everything again and then report it actually needs 2 blocks more because the par2 was damaged. Then we have to scan it again before it repairs, so in this example 3 scans for 1 repair.
This scanning might take a long long time on low power devices such as a raspberrypi or NAS, so better to download all par2 (especially on a fast connection) at once.

[kevindd992002]

Ah, that makes sense. But for most modern computers nowadays, this shouldn't be a problem, right? How big are ALL par2 files compared to the original size of the downloads anyway? Is there like a standard percentage or it really varies a lot from nzb to nzb?

[shypike]

Posting 10% par2 files is customary.