Syncing via Carbon Copy Cloner (GUI for rsync) fails due to iTunesFS as a OS X FUSE volume being mounted without the "allow_root" or "allow_other" option

[porg]

Carbon Copy Cloner 5.1.28 on macOS 11.6.6 Big Sur

Reproduction

• Source: /Volumes/iTunesFS/Playlists/Devices/mp3player/
• Destination: /Volumes/mp3player/
• I click "Clone". It fails with:

CCC cannot read the contents of the source volume because they are inaccessible to the System Administrator user account.
CCC cannot back up to or from an OS X FUSE volume mounted without the "allow_root" or "allow_other" option.

Possible solutions

• It is comfortable to rsync via GUI as this also keeps a log history and I can easily look up when did I sync last time, how many fiels have it been, etc.
  • Is it possible to change the forementioned flags to what CCC requires?
• If not also ok, then I will simply use rsync in Terminal.

[znek]

Did you try using the FUSEOptionAllowOther default?
You can make it permanent via:

defaults write com.mulle-kybernetik.znek.iTunesFS FUSEOptionAllowOther -bool true

[porg]

Wow!

With FUSEOptionAllowOther you can use CCC for syncing and astonishingly it succeeds in two regards:

1. No error message in CCC, so allow_other was successfully performed by macFUSE.
2. The syncing works not only the first time, but also the second and third time successfully skips files present on the FAT16 destination, which I did not expect! CCC seems to be intelligent enough to know which limited file metadata is available on the FAT16 target destination, and seems to only consider a limited set of rsync attributes to compare source and destination to determine which files are the same and which ones indeed changed.

• As I really did not expect that intelligent behavior of CCC I had already worked out a manual rsync command line, before receiving your hint to use FUSEOptionAllowOther.

So good to know for everyone

• You can conveniently use Carbon Copy Cloner to sync from iTunesFS to a FAT16 destination volume.
• Or use rsync in the Terminal with limited comparison attributes to sync reliably to a FAT16 volume.

[porg]

• Leaving this open as a reminder to may include this in the Readme and FAQ.
• Feel free to close when you see fit.