Broken ZFS boot on upgrade

Jonathan Anderson jonathan.anderson at
Mon Nov 11 20:14:02 UTC 2019

On 11/11, Andriy Gapon wrote:
> You need to find out the inode number first (ls -i or stat -s).
> Then you can use zdb -ddddd <zfs dataset> <inum>

That's very helpful, thanks! I've attempted to do this, but zdb is giving
surprising errors. My root dataset is mounted at /mnt/zroot:

zroot/ROOT/default on /mnt/zroot (zfs, local, noatime, nfsv4acls)

and ls -i /mnt/zroot gives me inode numbers for things in / (including /boot),
but when I execute zdb with that dataset and inode number I get an error:

# zdb -ddddd zroot/ROOT/default 4495
failed to own dataset 'zroot/ROOT/default': No such file or directory
zdb: can't open 'zroot/ROOT/default': No such file or directory

This despite zpool status saying that everything is fine, me being able to run
`find /boot` with no errors, etc. I get the same error whether the dataset is
mounted or unmounted.

At this point I'm probably best off flattening this system and restoring my most
recent backup snapshot, but this behaviour is truly curious.

Thanks to everyone for your help,

Jonathan Anderson

jonathan at

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