Sometime later, probably in October 2019, I decided I needed to move 110 GB of files off my Macbook Pro laptop's internal drive and onto a external drive. I also wanted to access this drive from Linux, and thought I'd just use a NTFS-formatted drive so it would be readable there.
I copied the files over using rsync and there seemed to be no problems, until I (in a fit of paranoia) ran the Unix cmp command on all the files on the original disk and the matching files on the NTFS-formatted drive. There were lots of differences. Uh oh.
I didn't see anything on the Internet complaining about this.
I wanted to try the same thing and see if it worked more reliably with extFS. I originally wrote short shell scripts for this, for consistency, so I could just change the volume name and run them again. Again there were lots of differences. Uh oh.
Again, I didn't see anything on the Internet complaining about this.
All I was doing was running
rsync -avz with the appropriate
directories; it should have worked.
I formatted the drive to Mac OS Extended (Journaled) and recopied the files, and this time they all compared ok.
I decided to just use Unison to sync the files to a couple of my computers for backup and local use instead of connecting the external drive to each computer in turn. This is working ok for me.
Maybe this was user error on my part, but it happened consistently with both of these file systems.