kern/158839: ZFS Bootloader Fails if there is a Dead Disk

[Felix]

>Number:         158839
>Category:       kern
>Synopsis:       ZFS Bootloader Fails if there is a Dead Disk
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Jul 12 16:10:12 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Felix
>Release:        8.2-RELEASE
>Organization:
>Environment:
FreeBSD nyx.my.domain 8.2-RELEASE FreeBSD 8.2-RELEASE #0: Thu Feb 17 02:41:51 UTC 2011 root at mason.cse.buffalo.ecu:/usr/obj/usr/src/sys/GENERIC amd64
>Description:
When booting with a dead disk using a raidz1 zfs boot, zfs fails to boot with the following message:

ZFS: i/o error - all block copies unavailable
ZFS: can't read MOS object directory
Can't find root filesystem - giving up
ZFS: unexpected object set type 0
ZFS: unexpected object set type 0

FreeBSD/i386 boot
Default: zroot:/boot/kernel/kernel
boot:
>How-To-Repeat:
Have a dead disk in a zpool and reboot a few times.
>Fix:
The problem can be temporarily fixed by removing the disk and running zpool import from a boot disk livefs.

>Release-Note:
>Audit-Trail:
>Unformatted: