On Thu, Jul 19, 2012 at 5:29 AM, Hans J. Albertsson
<hans.j.alberts...@branneriet.se> wrote:
> I think the problem is with disks that are 4k organised, but report their
> blocksize as 512.
> If the disk reports it's blocksize correctly as 4096, then ZFS should not
> have a problem.
> At least my 2TB Seagate Barracuda disks seemed to report their blocksizes as
> 4096, and my zpools on those machines have ashift set to 12, which is
> correct, since 2¹² = 4096
> You cannot mix 512 and 4096 byte blocksize disks in one pool, at least not
> in a mirror. All disks in a single pool should have the same blocksize.
> There is a hacked version of zpool for OpenIndiana that has a blocksize
> option to the create subcommand. I don't know if other OSes have similar
> fixes.

FreeBSD includes the gnop(8) command which can be used to create
pseudo-devices that declare any size of sectors you want.  This can be
used to create ashift=12 vdevs on top of 512B, pseudo-512B, or 4K

# gnop -S 4096 da{0,1,2,3,4,5,6,7}
# zpool create pool raidz2 da{0,1,2,3,4,5,6,7}.nop
# zpool export pool
# gnop destroy da{0,1,2,3,4,5,6,7}.nop
# zpool import -d /dev pool

Freddie Cash
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