No ZFS when loading modules from loeader prompt

Freddie Cash fjwcash at
Fri Feb 22 02:19:04 UTC 2013

I haven't used BEs yet, as I have no ZFS-on-root systems. I just know
that's how they're supposed to work, and that's the desired use case for

Vermaden from FreeBSD Forums would be a better one to ask, as he uses them
a lot and was one of the people behind BE support in FreeBSD.
On 2013-02-21 4:38 PM, "Peter Jeremy" <peter at> wrote:

> On Wed, Feb 20, 2013 at 7:05 AM, O. Hartmann <ohartman at>
> wrote:
> > At the loader prompt, I need to unload the buggy kernel and load the old
> > working one via
> >
> > load /boot/kernel.old/kernel
> >
> > Then I load also the ZFS related modules
> >
> > load /boot/kernel.old/opensolaris.ko
> > load /boot/kernel.old/zfs.ko
> >
> > Issuing boot at the end of that stage boots the kernel - the old one
> > -successfully - but there is no working ZFS and no ZFS volume gets
> > mounted although the rc.conf is executed correctly.
> >
> > What am I doing wrong at that point? Why isn't ZFS run and mount
> properly?
> Last time I ran into this problem, the issue was that "unload" also
> unloaded the zpool.cache file and the ZFS code relied on that to find
> the kernel.  I don't recall what the workaround was.
> On 2013-Feb-20 08:17:46 -0800, Freddie Cash <fjwcash at> wrote:
> >Sounds like a perfect use case for Boot Environments.  Create a new BE,
> >install the new kernel into it, set it as the default, reboot.  If it
> >fails, you manually set the previous BE as the default, and reboot.  That
> >way, your "known-good", working environment is never affected.
> How do you change your BE in the loader?  Or how do you change your
> BE when you can't boot?
> --
> Peter Jeremy

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