Note for those pulling in new ZFS feature flags

[Tom Evans]

On Mon, Apr 7, 2014 at 2:54 PM, Chris Nehren
<cnehren+freebsd-stable at pobox.com> wrote:
> Not too long ago I upgraded my FreeBSD workstation to 10-STABLE
> from 10-RELEASE in order to try newcons.  After I upgraded to
> 10-STABLE, I saw in `zpool status` that my pools could be
> upgraded to a new version of ZFS.  I did this, and then needed to
> reboot the machine for unrelated reasons.  When it came back up,
> it refused to boot because gptzfsboot couldn't import the pools.
>
> I solved this by re-running `gpart bootcode` for the afflicted
> drives.  This was a bit trying, though, as my workstation is the
> only FreeBSD machine I have readily available.  So, for those
> upgrading their zpools, be careful and remember to fix the
> bootcode if you're using ZFS for the root filesystem.

ISTR that "zpool upgrade" will also remind you to do this if bootfs is
true for the pool you upgraded.

Also, it is always worth having around a bootable memstick available
with the zfs code you are actually running in order to use as a
recovery disk in circumstances like this.

Cheers

Tom