Re: GPT boot with ZFS RAIDZ "ZFS: i/o error - all block copies unavailable"

On Thu, 2009-10-15 at 21:37 +0200, Radek Valášek wrote:
> Robert Noland napsal(a):
> > On Thu, 2009-10-15 at 14:08 +0200, Radek Valášek wrote:
> >   
> >> Hi,
> >>
> >> I want to ask if there is something new in adding support to 
> >> gptzfsboot/zfsboot for reading gang-blocks?
> >>    

I think that the gang block patch will work, though still haven't gotten
it tested.  However, I'm fairly confident that the issue is not gang
block related.  Right now, I have setup a disk like this:

=>        34  1953525101  ada1  GPT  (932G)
          34         128     1  freebsd-boot  (64K)
         162     8388608     2  freebsd-swap  (4.0G)
     8388770   648019968     3  freebsd-zfs  (309G)
   656408738   648019968     4  freebsd-zfs  (309G)
  1304428706   648019968     5  freebsd-zfs  (309G)
  1952448674     1076461        - free -  (526M)

Note that this is not a raidz pool right now.  It is just 3 toplevel
partitions setup as a single pool.  I finally have this configuration
working reliably.  At least in this case, the issue is due to all of the
partitions not being probed during early boot and so not being added to
the list of vdevs for the pool.  When zio_read finds a dva that points
to a device it doesn't know about, it gives up and whines.

Can you detail for me how you have everything configured, so that I can
try to replicate it.  gpart show, zpool status and zpool get all <pool>
would be good.  I'm not sure that I have enough spare disks lying around
to do this properly, but maybe I can use virtual disks or something.

robert.

> > Ok, I can't figure out any way to test this... beyond the fact that it
> > builds and doesn't break my currently working setup.  Can you give this
> > a try?  It should still report if it finds gang blocks, but hopefully
> > now will read them as well.
> >
> > robert.
> >
> >   
> Big thanks for the patches Robert, I will definitely test them as soon 
> as possible (tomorrow) and report the results immediately to list. I can 
> repeat this issue probably at any time (up to cca 30 times tested with 
> the same result), so don't bother about the broken booting, I'm prepared 
> for it...
> 
> vaLin
> >>  From Sun's docs:
> >>
> >> Gang blocks
> >>
> >> When there is not enough contiguous space to write a complete block, the ZIO
> >> pipeline will break the I/O up into smaller 'gang blocks' which can later be
> >> assembled transparently to appear as complete blocks.
> >>
> >> Everything works fine for me, until I rewrite kernel/world after system 
> >> upgrade to latest one (releng_8). After this am I no longer able to boot 
> >> from zfs raidz1 pool with following messages:
> >>
> >>  >/ ZFS: i/o error - all block copies unavailable
> >> />/ ZFS: can't read MOS
> >> />/ ZFS: unexpected object set type lld
> >> />/ ZFS: unexpected object set type lld
> >> />/
> >> />/ FreeBSD/i386 boot
> >> />/ Default: z:/boot/kernel/kernel
> >> />/ boot:
> >> />/ ZFS: unexpected object set type lld
> >> />/
> >> />/ FreeBSD/i386 boot
> >> />/ Default: tank:/boot/kernel/kernel
> >> />/ boot:
> >> //
> >> /I presume it's the same issue as talked in june-2009 current mailing 
> >> list 
> >> http://lists.freebsd.org/pipermail/freebsd-current/2009-June/008589.html
> >>
> >> Any success in that matter?
> >>
> >> Thnx for answer.
> >>
> >> vaLin
> >> _______________________________________________
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> >>     
> 
-- 
Robert Noland <rnoland_at_FreeBSD.org>
FreeBSD