[CentOS] Disk usage incorrectly reported by du

The space used by hard-linked files will be included only in the first

> directory where they are encountered.  In your first case, linked files
> seen prior to the /51 directory would not have had their space included
> again under that directory. In the second case, _only_ the /51 directory
> is being examined, so all space will be included.
>
> --
> Bob Nichols     "NOSPAM" is really part of my email address.
>                  Do NOT delete it.
>

Thank you, this makes sense. I was starting to worry that the filesystem is
broken.  I'll modify my rsync command to preserve hard links.

Radu