> My first guess would be that some items on your internal drive are
> hardlinked, and that when you rsync, those items are being created on the
> external drive as separate files with each copy taking up space. And I can
> confirm by inspection that there are many hardlinked items inside the Xcode 9
> app, for example. There's a flag you can supply to rsync ("--hard-links") to
> tell it to detect and recreate hard links on the destination drive, which
> should eliminate this reason for the size difference.
that sounds like a good excuse. I will try that. Thanks!
> I also thought of different block sizes, but ever since HFS+ in Mac OS 8.1
> block sizes are probably the same on all drives so that's unlikely to be
> relevant.
I agree.
"S'il n'y a pas de solution, c'est qu'il n'y a pas de problème" (devise Shadok)
