Dropbox issues when moving ~/Dropbox folder to a zfs filesystem

[captain-haddock17]

Hi !

When I move my ~/Dropbox folder to a ZFS /Volumes/zDisk/User/myuser through the Dropbox utility, I have the following :

1. transfer is OK
2. next time Dropbox tries to sync, it hangs forever .

I did tried to have some clues about the particularities of ZFS folder, no way.

I had to go back, with a complete rm -r ~/.dropbox because otherwise Dropbox.app was still referencing /Volumes/zDisk/User/myuser/Dropbox. (I was in a kind of deadlock) This way I could get a fresh ~/Dropbox folder on a APFS (or JHFS+) volume.

Eventually, I found on Dropbox's website some indication that it can't handle external disks and network filesystems. Dropbox has to capture some disk events

see Dropbox.com : Move a Dropbox folder to a new location

So why is ZFS filesystem not compatible ?

Software versions and params MacOS 10.14.6 Mojave name -a

Darwin macpro.home 18.7.0 Darwin Kernel Version 18.7.0: Mon Feb 10 21:08:45 PST 2020; root:xnu-4903.278.28~1/RELEASE_X86_64 x86_64

ZFS v1.9.0 sysctl -a {zfs,spl}

zfs.kext_version: 1.9.4-0 spl.kext_version: 1.9.4-0

ZFS params zfs get aclmode,aclinherit,xattr,utf8only,normalization,casesensitivity,com.apple.browse,com.apple.ignoreowner,com.apple.mimic_hfs,com.apple.devdisk zDisk/Users/William

NAME PROPERTY VALUE zDisk/Users/william aclmode passthrough zDisk/Users/william aclinherit restricted zDisk/Users/william xattr sa zDisk/Users/william utf8only on zDisk/Users/william normalization formD zDisk/Users/william casesensitivity insensitive zDisk/Users/william com.apple.browse off zDisk/Users/william com.apple.ignoreowner off zDisk/Users/william com.apple.mimic_hfs on zDisk/Users/william com.apple.devdisk poolonly

[captain-haddock17]

to double cross-check, I did another test with carefully applying the chflags / chown / chmod instructions on ZFS Dropbox folder. No way !

Note : I have the same issue with 2 other users accounts on my rig.

[captain-haddock17]

Did some other cross-check test :

As ZFS seems to presents himself as a Disk image (? needs confirmation), I did a test with a regular/plain MacOS DiskImage file mounted in my user space (APFS).

with a Disk image as Dropbox folder, I do not have this sync issue.

So I wonder where the problem is ... I suspect some MacOS apps need to interact with the filesystem through some event-driven framework.

I encountered other weird phenomena when opening a folder on zfs with some IDE (Textmate.app ; VS Code.app) when a subfolder has been updated by other app (i.e. compiler). I'll try to document this later.

HTH.... william

my ZFS disk is seen as : diskutil info disk6s1

Partition Type: ZFS Dataset File System Personality: ZFS Type (Bundle): zfs Name (User Visible): ZFS Dataset

OS Can Be Installed: No Media Type: Generic Protocol: Disk Image (...) Device Location: Internal Removable Media: Fixed

my DiskImage

Partition Type: 41504653-0000-11AA-AA11-00306543ECAC File System Personality: APFS Type (Bundle): apfs Name (User Visible): APFS Owners: Disabled (...) Media Type: Generic Protocol: Disk Image (...) Device Location: External Removable Media: Removable Media Removal: Software-Activated

[lundman]

When it hangs, could you run "sudo spindump" and see if it has stacks stuck