I am not sure to know which flag did the trick, but indeed now my Application Folder is 22 Gb like in the internal drive. Thanks a lot
> Le 26 oct. 2017 à 14:19, Jim Jagielski <[email protected]> a écrit : > > When using rsync on HFS+, I tend to always use the following options: > > rsync --archive --crtimes --hard-links --acls --xattrs --fileflags > --force-change --protect-decmpfs > > On Thu, Oct 26, 2017 at 6:22 AM, Ryan Schmidt <[email protected] > <mailto:[email protected]>> wrote: > > On Oct 26, 2017, at 04:28, pagani laurent wrote: > > >> 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. > > > > Did not work. I erased Xcode again and rsync’ed it with —hard-links. Size > > remains the same. 12 Gb instead of 7.8 local. > > I can only confirm your observation. My original Xcode.app is "10,581,631,771 > bytes (5.76 GB on disk)" according to the Finder's Get Info window, while an > rsync'd copy with --hard-links is "10,511,782,504 bytes (11.12 GB on disk)". > As a result, I now question whether it's possible to create an accurate copy > of a macOS disk using rsync. > > The rsync manpage mentions --hard-links not being a default because finding > hard links is expensive. Maybe there is an upper limit to the number or size > of files rsync is willing to analyze to find hard links; if so, maybe what > we're doing exceeds that limit. > > Maybe Xcode and other things on your original disk are making use of > directory hard links, a feature Apple implemented so that Time Machine could > be more efficient, but which rsync doesn't know about. I read about this here: > > https://arstechnica.com/civis/viewtopic.php?f=20&t=1108222 > <https://arstechnica.com/civis/viewtopic.php?f=20&t=1108222> > > It's also mentioned there that you can use "cpio -pdl" somehow to reunite > inadvertently duplicated files with one another as hard links, though I'm not > sure what it will do if you have any identical files that are supposed to > remain unlinked. > > > "S'il n'y a pas de solution, c'est qu'il n'y a pas de problème" (devise Shadok)
