Mounting from zfs:zroot/ROOT/default failed with error 2: unknown file system after upgrade to 10.1-RELEASE

[Trond Endrestøl]

On Wed, 19 Nov 2014 18:47+0100, Anton Eliasson wrote:

> Den 2014-11-19 18:17, Trond Endrestøl skrev:
> > To break into the kernel debugger, enter this before booting the
> > kernel:
> > 
> > set debug.debugger_on_panic="1"
> > 
> > Judging from the screenshots you've provided and from what you wrote
> > in your reply, it seems vfs.root.mountfrom is overridden somehow.
> > /boot/loader.conf would be a natural candidate.
> > 
> > If the bootfs property is indeed set to zroot/ROOT/default, then it's
> > very strange that the kernel would proclaim:
> > 
> > Trying to mount root from zfs:zroot []...
> > 
> > instead of:
> > 
> > Trying to mount root from zfs:zroot/ROOT/default []...
> > 
> > And it's even stranger that nothing appears on lszfs' radar when asked
> > to list zroot/ROOT/default.
> > 
> > > Selecting the old kernel in the boot menu and trying to boot normally
> > > fails
> > > because init is not found:
> > > https://cloud.solid.lth.se/public.php?service=files&t=81fd35bb6348ae7426553c2f59fb2a18
> > > 
> > > Could this be a mismatch in kernel and kernel module versions? How would I
> > > fix
> > > that?
> > If you can boot from a recent snapshot image or live image, and import
> > the zpool read-only, you could walk around and see if
> > zroot/ROOT/default/boot/loader.conf contains anything strange.
> > 
> > This zpool command would allow you to go spelunking inside /zroot:
> > 
> >    zpool import -o readonly=on -f -R /zroot zroot
> > 
> > You might need to mount readonly any dataset you wish to examine.
> > 
> > If you see the need for changing any of the files, you must export the
> > zpool and re-import it readwrite, i.e. leave out the -o readonly=on
> > option.
> > 
> > I admit I'm in unknown territory, even if I have managed multiple ZFS
> > systems over the past years, so be careful.
> > 
> Hi!
> I had forgot to remove the vfs.root.mountfrom that I experimented with. This
> probably caused the failure to load init.
> 
> I got it to work by chrooting into the system from a live cd and rolling back
> the upgrade with `freebsd-update rollback`. Then it booted fine. Now
> freebsd-version shows 10.0-RELEASE-p12 and uname -r shows 10.1-RELEASE. It
> looks a bit strange, but at least it works for now.
> 
> I may have mixed up the commands used to upgrade the system. Is the following
> the correct procedure for doing a major upgrade (with a stock kernel)?
> 
> freebsd-update -r 10.1-RELEASE upgrade
> freebsd-update install
> (reboot)
> freebsd-update install
> (rebuild ports)
> (done)

Sadly, I wouldn't know.

I use the Subversion base/stable source tree for the OS, be it 
base/stable/{8,9,10}, and the ports collection (ports/head) for any 
3rd party SW.

On my ZFS systems I always install a new world and kernel into a new 
dataset, zroot/ROOT/YYYYMMDD-rRRRRRR, (maybe I'll eventually settle 
for a snapshot + clone + install dance), adjust the bootfs property on 
the root pool, copy select files from /boot, /etc, and /root to the 
new dataset, let the new dataset inherit the mountpoint (legacy) from 
its parent, and reboot into single user mode to perform basic 
maintenance such as mergemaster and make delete-old, and maybe I even 
upgrade any outdated ports using portupgrade and a homegrown shell 
script, before I cold boot the system to verify the system's ability 
to bootstrap itself, and to allow the harddrives to do their power-on 
maintanance.

In stable/10 and head, you can now have options ZFS in a custom kernel 
configuration, removing the need to load opensolaris.ko and zfs.ko 
along with the kernel. The freebsd-update route allows only for the 
GENERIC kernel and a precompiled world. :-/

> Thanks for your help!

NP. :-)

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| Trond Endrestøl,              | Trond Endrestøl,                   |
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