MultiPar VS par2cmdline

but... depending on how much effort you want to spend fixing it I might be able to fix your current corrupt files, especially if the corrupt files are only mildly corrupt I could create a '.par2' file from mine (assuming you are on build 1436.28), then you would use MultiPar (i.e. https://github.com/Yutaka-Sawada/MultiPar/releases ) to scan your files and it will tell me how many blocks you need to fix it and then I could create recovery data with MultiPar. doing this might dramatically lower the amount of data I would have to upload as then you could use MultiPar which will fix your current corrupt files so they match mine identically.

MultiPar is the continuation for Windows https://github.com/Yutaka-Sawada/MultiPar

And this for Linux https://github.com/animetosho/par2cmdline-turbo

* MultiPar supports in-situ repair, which bypasses this problem entirely

To detect bitrot I use dynamix file integrity plugin, it compute Blake3 hash for each file, it is stored as extend attribute. You Can choose which share will be covered. For correction i then use par2 files using multipar https://hp.vector.co.jp/authors/VA021385/ https://github.com/Yutaka-Sawada/MultiPar (Windows only, par2cmdline for Linux. You could compile from source and add it to unraid if you want, i've done it for testing purpose)

And last but not less important - make regular parity files of your healthy important data, and store them somewhere. MultiPar is your best friend. Even if your data gets corrupt, with parity files you can restore it to it's former glory. Some limitations will apply, read the manual.

This is possible with MultiPar https://github.com/Yutaka-Sawada/MultiPar

More sanely, perhaps, get some M-Disc DVDs (if you can find real ones - apparently they're becoming just normal DVDs) and put one file on each, and then run https://github.com/Yutaka-Sawada/MultiPar on it to create parity files. Then store the file, the parity files, and the software you need (MultiPar) on the disc. To be safe, you probably also need to store the DVD burner you used to make it, as those are getting thin on the ground these days.

Note about par2: if one is using a windows system with a nvidia GPU this version of par2 is faster as it speaks CUDA.

For any file repairs use multipar, it's still being updated and has gpu acceleration. https://github.com/Yutaka-Sawada/MultiPar/releases

An alternative is including PAR2 files.

Not only that but if you budget for an expected error rate of let's say 10% you can use par2 to create additional files that add that redundancy to your archives.

https://github.com/Parchive/par2cmdline

That's the same reason I do archive files. For parity I personally use (https://github.com/Parchive/par2cmdline) which does create extra files, so I can see how WinRAR would have something to add there.

Here's the first example I could find.

https://pthree.org/2014/04/01/protect-against-bit-rot-with-p...

Basically, you take a normal TAR file and creates external parity files that can be used to recover data in the case of bitrot. Something like this would have been great to have on a few data files I had to retrieve from tape that ended up with a bit flip somewhere in the network > disk > tape > disk process.

However, it doesn't look like the program is maintained anymore...

http://parchive.sourceforge.net/

> DISCLAIMER: This project web space is not actively mantained and is presented here for archive purposes. However some project members still montior the project mailings lists if you have questions. (sic)

The last release was in 2004 (Wikipedia says it was active until 2015, but I don't see that).