mount root from zfs fails under current with "error 6"

[Michael Reifenberger]

On Mon, 30 May 2011, Garrett Cooper wrote:
...
>    dmesg for starters (boot -v if possible) would be extremely
> helpful. More details like your disk subsystem that you're booting off
> of, whether you're using GPT/MBR when booting via ZFS, etc would be
> helpful. Also being able to better trace down the root cause would be
> nice (not being able to boot a recent kernel, but being able to boot a
> kernel from almost a month ago is unfortunately a bit of a non-starter
> for tracking down the actual issue because that's such a long span of
> time).

Ok.
Verbose boot output is available here:
 	http://people.freebsd.org/~mr/boot_fail.txt
 	http://people.freebsd.org/~mr/boot_success.txt

Verbose pciconf output:
 	http://people.freebsd.org/~mr/pciconf.txt

Disksetup:
Im booting from 4 equally GPT partitioned 3TiB Disks:
(fs)(root) gpart show ada0
=>        34  5860533101  ada0  GPT  (2.7T)
           34         990     1  freebsd-boot  (495k)
         1024     2098176     2  freebsd-swap  (1.0G)
      2099200  5858433928     3  freebsd-zfs  (2.7T)
   5860533128           7        - free -  (3.5k)

(fs)(root) zpool status boot
   pool: boot
  state: ONLINE
  scan: scrub repaired 0 in 5h2m with 0 errors on Mon May 30 08:03:43 2011
config:

         NAME        STATE     READ WRITE CKSUM
         boot        ONLINE       0     0     0
           raidz1-0  ONLINE       0     0     0
             ada0p3  ONLINE       0     0     0
             ada1p3  ONLINE       0     0     0
             ada2p3  ONLINE       0     0     0
             ada3p3  ONLINE       0     0     0

errors: No known data errors

(fs)(root) zpool get bootfs boot
NAME  PROPERTY  VALUE           SOURCE
boot  bootfs    boot/ROOT/root  local

# loader.conf:
...
vfs.root.mountfrom="zfs:boot/ROOT/root"
...

BTW:
After suspecting the new ada alias code I set:
 	kern.cam.ada.legacy_aliases=0
But without effect.

@pjd:
Could you tell why/when the ZFS mount code errors with ENXIO?

Thanks all for investigating!

Bye/2
---
Michael Reifenberger
Michael at Reifenberger.com
http://www.Reifenberger.com