I recently built a new server and part of that was using 4 new 2TB NVMe drives to use in a Mirror/Raid 10 cache setup in zfs. It is sweet!

I have exclusive share set on and the likes of appdata, system, domains, have been happily using this for a few months or so now. These shares (and the folders under appdata) each have individual datasets within the main zfs_cache.

root@NAS:~# ls -ld /mnt/user/system

readlink /mnt/user/system

lrwxrwxrwx 17 root root 20 Nov 4 14:41 /mnt/user/system -> ../zfs_cache/system/

../zfs_cache/system

I tried to install a new docker/app "webgrabplus" and it appears there is a non-unicode character in a filename which by all accounts installs fine on a non-zfs setup, but on mine it would not install.

I created an issue on Github thinking it was an error in the docker build. That post is here. Someone kindly posted a screenshot of the app installing OK on their Unraid system without ZFS.

Having also read this post it appears, perhaps, that the extraction process fails with a ZFS locale / overlay2 unpack issue inside the docker layer itself which is on the exclusive 'system' share. As a result the error below occurs and the container fails to install at all.

"Error: failed to register layer: open /defaults/ini/siteini.pack/International/sat.tv.channels.13?E-Arabesque.xml: invalid or incomplete multibyte or wide character"

The '?' in 13?E is a ° degree symbol.

What is a solution to this edge case I have?!!

nas-diagnostics-20251107-1305.zip

Edited November 8, 2025Nov 8 by Bob_C
Tidy

Try using a docker image instead of a folder; that should not have the zfs limitations.

Thanks for the quick feedback.

What are the implications for doing this? I just read this on the docs:

"If you are using Docker data-root=directory on a ZFS volume, we recommend that you navigate to Settings → Docker and switch the Docker storage driver to overlay2, then delete the directory contents and let Docker re-download the image layers. The legacy native setting causes significant stability issues on ZFS volumes."

Not sure I want to go to an image if it has stability issues? Or have I read that wrong?

17 minutes ago, Bob_C said:

Not sure I want to go to an image if it has stability issues? Or have I read that wrong?

It's talking about using a directory. @JorgeB wants you to switch to using a docker image

2 hours ago, Bob_C said:

Not sure I want to go to an image if it has stability issues?

Images are typically less prone to issues than folders. In my experience, they can cause strange issues. It may be worth a try; you can always revert to a fodler if you like.

https://docs.unraid.net/unraid-os/troubleshooting/common-issues/docker-troubleshooting/#re-creating-the-docker-image-file

Then:

https://docs.unraid.net/unraid-os/troubleshooting/common-issues/docker-troubleshooting/#reinstalling-docker-applications

Also see below if you have any custom docker networks:

https://docs.unraid.net/unraid-os/troubleshooting/common-issues/docker-troubleshooting/#restoring-docker-custom-networks