How to mirror one folder to another using rsync 3.x

You could use, Automator and Folder actions to watch the folder and run the script.

When launching Automator and choosing New, one of the options given is to make a 'Folder Action'. At the top of the screen after selecting Folder Action you are given the option to choose a folder to 'watch'.

What I think you would want to do in your case is to then select 'Utilities' on the leftmost column, and then drag 'Run Shell Script' from the second column into the workflow window.

Here is where you would write whatever script you would like to run when changes are made to the folder. In this case your rsync script.

Check out the man page for rsync. In particular, the -a (archive) option you show will invoke the -rlptgoD options.

• -r, --recursive (recurse into directories)
• -l, --links (copy symlinks as symlinks)
• -p, --perms (preserve permissions)
• -t, --times (preserve times)
• -g, --group (preserve group)
• -o, --owner (preserve owner (super-user only))
• -D (preserve device and special files)

Permissions can be preserved, but everything you copy will be owned by you unless you run under sudo so the -o option will take effect. Also note that without sudo, rsync gives you no special abilities to copy files that you do not have access to on the source drive.

You may also want to look at the -E option, but I don't know if it will work from an NTSF drive. Maybe it will preserve ACLs (if they exist on the source)?