Boot with ZFS on single disk: "ZFS: i/o error - all block copies unavailable" [was: Re: GPT boot with ZFS RAIDZ "ZFS: i/o error - all block copies unavailable"]

On Tue, 17 Nov 2009 23:33:41 +0100, Robert Noland <rnoland_at_freebsd.org>  
wrote:

>> Should I file a PR? I would
>> like to help in debugging it (however my skills in low-level C aren't
>> strong enough to do it on my own).

> Ok, the first thing I would like to see is "zdb -uuu".

# zdb -uuu pgpool
Segmentation fault: 11 (core dumped)

# zdb
pgpool
     version=13
     name='pgpool'
     state=0
     txg=439808
     pool_guid=3920915583055727184
     hostid=1642959122
     hostname='unset'
     vdev_tree
         type='root'
         id=0
         guid=3920915583055727184
         children[0]
                 type='disk'
                 id=0
                 guid=5859773264564918193
                 path='/dev/da0'
                 whole_disk=0
                 metaslab_array=23
                 metaslab_shift=35
                 ashift=9
                 asize=4500799356928
                 is_log=0
                 DTL=260

> I don't see an
> obvious issue with single disk reads.  My own setup uses 2 x 1TB
> currently.  Failing to read the MOS is basically the first read attempt
> from the pool, in fact it is the read that attempts to mount the pool.

-- 
am