[Nyan]

I see. Yeah, PAR3 tries to address the 'lots of files' scenario better than PAR2.

But updates are problematic. You could 'delete' parts of a recovery file if the data is present. However a file being updated typically means that the original data (before the update) is no longer present, meaning you can't really 'delete' that part of the recovery to replace it with the new data. You could try and retrieve the old data by recovering it, but at this point, it may just be easier to recreate the entire PAR set again.

If it's just adding to the recovery set, PAR3 does have provision for that.

[joshspankit]

I should thank you, though it’s also meant I’ve lost most of the last 3 days:

After our discussion I went and found the current work on PAR2/PAR3 (which, for those in the know: the current PAR3 format is not the old on the was never finished, but a spec that’s been re-written and is close to completion with real-world tools close behind) and I have a lot more hope for the future of parity files.

I still think they are wildly under-utilized (BackBlaze has always used them, but they are the only business I know of), but we might be having a different conversation in 2-3 years.