Several days ago, I posted an answer to the following question: rsync: identical files (contents, size, timestamp) between source and destination are not being seen as identical
A moderator deleted my answer. This is the answer which starts with the words "I give up". The moderator explained that this was done because my assessment of why my question cannot be answered was deemed to be premature. The moderator deleted this answer with a comment stating that the question should remain and be discussed by the community for a while before any answer like mine is accepted.
Well, after close to a week of discussion and investigation, it turns out that my answer that was deleted is indeed totally correct. You can see by the reading the latest answer offered by the very helpful user @roaima and the comments associated with his answer that his answer substantiates the validity of my own answer that was deleted.
In other words, the following statement I made in my deleted answer has now been shown to be totally correct:
rsynccannot be relied upon to operate correctly when sync'ing between an ext4 filesystem under linux and an APFS filesystem under MacOS.
I am therefore requesting that this deleted answer be reinstated, although the green check-mark should be removed in favor of @roaima's answer.
Another reason for this is because some comments that are associated with that deleted answer clarify other statements that have been made in the discussion of this question, and it would be beneficial if other readers of this question could read those clarifying comments.
I completely understand that my original answer was posted in frustration after not enough time had passed for a meaningful investigation and discussion of my question to be completed. However, the wholesale deletion of that answer seems to me to be an excessive over-reaction. All that needed to be done by the moderator (in my opinion) was to remove the green check mark that I put onto my original answer and to add a comment explaining why and asking me to wait before jumping to conclusions. Such a comment was indeed posted by the moderator, and so I believe that the answer deletion was not needed.
Anyway, I hope that my deleted answer will now be re-instated.
Original answer pasted below for <10k users to be able to view:
I give up.
I think that the only viable answer to my question is the following:
rsynccannot be relied upon to operate correctly when sync'ing between an
ext4filesystem under linux and an
APFSfilesystem under MacOS.
I have a mostly unused Mac sitting around, and I thought I could save some money by using it as an
rsync-based backup repository for my linux box, instead of going out and purchasing an extra USB drive for that purpose. It now seems like that was not the correct course of action.
PS: Please read "NOTE" in my original question, above. In that text, I clearly explain in detail how timestamp discrepancies between the two OS's could not be causing this problem. Thank you for taking the time to read that.
And it's already been made clear that this is not a file-size issue, either.
This problem seems to simply be due to differences in behavior between a linux
ext4filesystem and a MacOS
PPS: Per the suggestion below, I re-installed
rsyncvia homebrew on my Mac and retried the sync after having added
rsynccommand line (that's the location where homebrew installs it). Sadly, using that homebrew version of
rsyncdid not fix the problem.