File level parity checks

[dougsweetser-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org (Doug)]

Hello:

The few times I have lost files, I have been an unhappy camper.  This
is why I do sometimes do rsync backups to another hard disk (maybe
once a month).  On the Mac, there is a drive for time machine.

I vaguely recall reading somewhere, possibly here, about file level
parity checks.  I may have been backing up a corrupted file for years.
 I little reading led me to the command line tool par2.  Where there
once was 1 file, there are now 8, now taking up 4 times as much space.
 If I could hide any file ending in .par2 except when needed, the
clutter could be decrease.

Does anyone bother to use parity checks on the file level?  I would
think someone might have written a script to walk through a directory,
writing par2 files where needed.  Or is it the case that people just
use RAID #N?

Doug