Problems on Mac OS X with owners and groups? For solution,
mkoistinen at gmail.com
Tue Aug 30 14:34:02 GMT 2005
This message is placed here for the aid of others in the future. I have
search the archives for this solution, but sadly, only found a couple of
(rather old) messages from people exhibiting having the same problems, but
without any replies for this solution.
Please forgive me as I seem to ramble on here, I do so with the intent of
making this solution more findable by others having this issue but don't
exactly know what they are searching for.
The problem is characterized by copies made by rsync have reset owner and
group information -- in my case to root : unknown -- regardless of the
switch settings for rsync. So, for example:
# rsync -aog source dest
will copy all files from source to dest, but will not preserve the owner and
group settings of the source files, even though the (redundant) flags for -a
, -o and -g are all set.
To make matters worse, because of the problem, the whole --link-dest
functionality doesn't save space in a backup/snapshot scheme for unchange
files, since rsync will find that the dest files in the previous backup will
have different ownership than the source files (unless the source files also
happen to have root:unknown ownership, that is)
This problem is most likely to occur with those of us who have added extra
disks to the system (probably) via firewire or USB.
The issues is not rsync, but rather a setting in the OS. OS X has newly
formatted disks marked with a flag to "ignore ownership details on this
volume" by default. To fix this, select the volume you wish to check/change
in the finder. File -> Get Info (Apple-I), in the multi-panel, info-window
for your disk, open the section "Ownership & Permissions:", and
verify/uncheck the checkbox for "Ignore ownership on this volume".
Voila, the "rsync" issue is now gone.
I suspect that this ownership flag is set by default to emulate disk
insertion behavoir prior to OS X on the Mac (where it was ignorant of
ownership and/or permissions).
It would be great if rsync could verify that ownership settings actually
took when they are set and report in the verbose output and/or logs if there
is a discrepancy. This would help to aid those of us in setting up
rsync-based backups and will forewarn us of related problems during full
recovery of a backup.
I hope this helps someone and/or aids the future development of rsync.
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