Re: cannot boot: ZFS: unsupported feature" com.klarasystems:vdev_zaps_v2

From: mike tancsa <mike_at_sentex.net>
Date: Tue, 10 Dec 2024 17:47:32 UTC 
On 12/10/2024 12:10 PM, Dag-Erling Smørgrav wrote:
> Marco Beishuizen<mbeis.bsd@xs4all.nl> writes:
>> Quite unexpected (after a portupgrade) I suddenly can't boot anymore:
>>   
>> [...]
>> BIOS drive C: is disk0
>> ZFS: unsupported feature: com.klarasystems:vdev_zaps_v2
> For this to happen you must have either a) upgraded your pool without
> upgrading your boot loader, b) downgraded your boot loader, or c) booted
> from the wrong medium (e.g. a CD or USB stick you forgot to remove
> before rebooting).  Either way, portupgrade is not at fault.

The edge case I can think of is if some feature is not enabled in the 
pool and something that does zfs'y things (e.g. zrepl) that get upgraded 
to use those new features, it could lead to an issue like this.  IIRC, I 
ran into something like this but it was v2 bookmarks all of a sudden 
being used.

     ---Mike