Note for those pulling in new ZFS feature flags

[Trond Endrestøl]

On Mon, 7 Apr 2014 10:55-0400, Chris Nehren wrote:

> On Mon, Apr 07, 2014 at 15:36:21 +0100, Tom Evans wrote:
> > > 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.
> 
> I'm fairly certain there was no such message, or I would have
> dutifully done what it said.  I definitely do know there is a
> message of that kind when attaching a disk to a mirror, and I've
> followed through there without issue.

See:

http://svnweb.freebsd.org/base/stable/10/cddl/contrib/opensolaris/cmd/zpool/zpool_main.c?view=markup#l4992

Consider this a lesson learned. Yes, I too was bitten by this once, 
but never again. ;-) Luckily, I recovered using a snapshot image.

Whenever I upgrade a ZFS system which has a ZFS boot pool, I always 
upgrade the bootblocks even if I don't upgrade the boot pool to 
include some new cool zpool feature.

Nevertheless, it's still handy to have a recent snapshot available on 
physical media or as an image file at least.

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