rsync to Mac OS X question

Chris Heller heller at
Fri Aug 6 20:28:25 GMT 2004

I'm am currently setting up a simple backup system using rsync. I am
backing up users home directories to a central backup machine, and then
exporting those backups via NFS back to their host machines.

I had this set up and working under Linux (kernel 2.4.21) but have since
decided to give Mac OS X a try, and moved the system over to a brand new
Xserve G5.

It was actually quite painless to do, and everything seems set (even

I ran into a problem today when I tested the system for the first time.
I am rsyncing from a remote Linux host using the following options to
rsync: -avv --rsh="<ssh stuff here>" --exclude-from=<path to exclude
file> --delete.

The problem is when the files are moved over to the Mac OS X server
their owner/group ids change.

For instance if I copy ~heller/ (uid: 500 gid: 500) to the Mac it
becomes uid: 504 gid: 504.

This isn't too big a problem, but it messes up security when I go to
export the data via NFS.

>From the rsync man page I was under the impression that -a will preserve
owner, group permissions.

What I am wondering is this an issue with rsync, or is it caused by
something behind the scene on the Macintosh? Both the Mac and the Linux
machine are running rsync 2.6.2 (although I don't think it matters what
version the Mac runs).

Hopefully someone, more knowledgeable than me, can enlighten me on what
is going on.



_/_/_/_/ Chris Heller                         Network Systems
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_/_/_/   Teragram Corporation
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