[OpenIndiana-discuss] disk warning message

[Reginald Beardsley]

--- On Mon, 3/25/13, russell <stream at willows7.myzen.co.uk> wrote:

> From: russell <stream at willows7.myzen.co.uk>
> Subject: [OpenIndiana-discuss] disk warning message
> To: openindiana-discuss at openindiana.org
> Date: Monday, March 25, 2013, 6:39 PM
> Hi,
> 
> I am currently getting the following message from my boot
> disk
> 
> WARNING: Disk /dev/dsk/c6t3d0s0 has a block alignment that
> is larger than the pool alignment
> 
> Is there away to correct this problem with the minimum of
> fuss?

I've not seen that message, but it sounds as if you've got a pool w/ ashift=9 on a 4k disk.

Read these:

http://wiki.illumos.org/display/illumos/ZFS+and+Advanced+Format+disks

The part about reconfiguring using cfgadm discussed here:

http://blog.delphix.com/gwilson/2012/11/15/4k-sectors-and-zfs/

is important.  It took me several hours of puzzlement before I read it and figured out why things didn't seem to have any effect.

This is purely speculative, but if it's a mirror you might be able to detach the existing disk and then add it back properly aligned.  If that works it's pretty low fuss.  Most of the work is reading up on the task and setting sd.conf properly.  If it's a RAIDZ pool, you may be able to simply setup sd.conf, corrupt the disk using dd and then let ZFS resilver. 

I was able to build a 4 way mirrored root pool (s0) and a RAIDZ2 array (s1) on 4 disks doing games like this after installing from the Live DVD.  There's a brief description of my adventures here:

http://wiki.openindiana.org/oi/Building+a+small+NAS+using+OI 

Obviously the first step is good backups (i.e. at least two)

The current situation is a bit messy and not well documented.  It helps a lot to browse the source code in sd.c.

Good luck.
Reg