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

[Trond Endrestøl]

On Tue, 18 Nov 2014 23:05+0100, Anton Eliasson wrote:

> Hi!
> After upgrading a server from FreeBSD 10.0-RELEASE to 10.1-RELEASE it no
> longer starts up. The bootloader shows its usual menu and then proceeds to
> load zfs.ko, opensolaris.ko and some third module. Then kernel boots and
> continues all the way to mountroot where it fails with the message "Mounting
> from zfs:zroot/ROOT/default failed with error 2: unknown file system." The
> entire message:
> https://cloud.solid.lth.se/public.php?service=files&t=27c15a131ca63b19f619a7ee558fe8d1
> 
> Entering zfs:zroot, zfs:zroot/ROOT, zfs:zroot/ROOT/default or zfs:anythingelse
> results in the same error.
> 
> FreeBSD 10.0 was installed this summer. I believe I used the installer's
> guided procedure for installing on a mirrored ZFS root. Each drive has a GPT
> table with a 512k freebsd-boot, a freebsd-swap and a freebsd-zfs partition. No
> separate /boot.
> 
> There is no vfs.root.mountfrom directive in /boot/loader.conf and no / in
> /etc/fstab. If I set vfs.root.mountfrom="zfs:zroot" it fails with the same
> message but a slightly different path (zfs:zroot).
> 
> The motherboard is a Supermicro X9SRH-7TF. I can import and mount the root
> filesystem with a FreeBSD live CD without problems.
> 
> Some config files pulled from a very similar installation (same server model,
> installed at the same time). They should be more or less identical on the
> server that won't boot:
> 
> /etc/rc.conf:
> 
>     hostname="..."
>     keymap="swedish.iso.kbd"
>     # Use synchronous DHCP; pause boot until DHCP is completed.
>     ifconfig_ix0="SYNCDHCP"
>     sshd_enable="YES"
>     ntpd_enable="YES"
>     # Set dumpdev to "AUTO" to enable crash dumps, "NO" to disable
>     dumpdev="AUTO"
>     zfs_enable="YES"
> 
>     # IPFW
>     [...]
> 
> /boot/loader.conf:
> 
>     zfs_load="YES"
>     geom_mirror_load="YES"
> 
> /etc/fstab:
> 
>     fdesc    /dev/fd        fdescfs        rw    0    0
>     /dev/mirror/swap none swap sw 0 0
> 
> Thanks!

According to the screenshot, the bootfs property on zroot is set to 
zroot/ROOT/default. Does that dataset exist?

While at the loader prompt, what does these commands tell you?

  lszfs zroot
  lszfs zroot/ROOT

If you see some other potential dataset, try setting currdev using 
this as a template before booting:

set currdev="zfs:zroot/ROOT/some-other-dataset:"
                ^                             ^
                    These :'s are important.

Next, unload the old stuff, and try to load the new stuff:

unload
load /boot/kernel/kernel
load /boot/kernel/opensolaris.ko
load /boot/kernel/zfs.ko

Boot into single user mode:

boot -s

Remember, the console uses US keyboard layout, set up by the firmware.

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