After installing or upgrading to Ubuntu 21.10, with the ZFS option, I started to experience strange issues.
For example, on the command-line, I have started to see errors like this:
Cannot access 'foobar': No such file or directory
When running ls -l in some directory, I get question marks, like this:
-????????? ? ? ? ? ? foobar.txt
-????????? ? ? ? ? ? foobar2.txt
Eventually, I couldn’t even boot Ubuntu 21.10 (that uses ZFS).
>Solution :
This is a known issue. The release notes for Ubuntu 21.10 say:
Known Issues
Linux kernel
- The version of the ZFS driver included in the 5.13.0-19 kernel contains a bug that can result in filesystem corruption. Users of
ZFS are advised to wait until the first Stable Release Update of the
kernel in 21.10 before upgrading.
I recommend this course of action:
- If you are installing Ubuntu 21.10, do not select the ZFS option. This will result in filesystem corruption, which you do not want.
- If you are upgrading to Ubuntu 21.10, and you’re using ZFS, don’t, until the fix has been released and users are no longer been reporting issues. (As of writing, the fix hasn’t been released yet.)
If you have already upgraded to Ubuntu 21.10, you can revert to your old filesystem by choosing the "Revert" option in the boot menu (grub). Press del while booting up to display this boot menu.