What layer of the filesystem it should be handled at can be debated (a tar with separate PAR2s? a single archive split into multiple ZFEC shares?) but that sort

What layer of the filesystem it should be handled at can be debated (a tar with separate PAR2s? a single archive split into multiple ZFEC shares?) but that sort of thing is precisely what a long-term archiving tool should be handling for you. I don't want to mess with par2create by hand anymore than I want to try Imagemagick on multiple settings to get an acceptable tradeoff.