[OpenIndiana-discuss] 4k sectors, how to create a root pool with the correct ashift value

[Hans J. Albertsson]

Some people on this list have referred to a "guru" way of fixing this.
So I thought to try and find out how to do this, for a server install 
I'm just about to perform.

First: my server is an X8STi-F motherboard, with two 2TB disks, 
ST2000DM001 Barracuda 2TB, 7200rpm, 64MB, SATA 6Gb/s
If someone can assure me this will cause no problem, and that installing 
from the DVD will create a root pool with the proper ashift, I don't 
need any more advice.

Otherwise, if the defaults will cause the root pool to be created with 
the wrong ashift, I want to know how to work around the problem.

Can one do something like creating the zpool from the live DVD? Or is it 
more difficult?

Please enlighten me!

On 2012-02-15 11:46, openindiana-discuss-request at openindiana.org wrote:
> Message: 8
> Date: Wed, 15 Feb 2012 09:24:26 +0100 (CET)
> From: Roy Sigurd Karlsbakk<roy at karlsbakk.net>
> To: Discussion list for OpenIndiana
> 	<openindiana-discuss at openindiana.org>
> Cc: Illumos Discussion<discuss at lists.illumos.org>
> Subject: Re: [OpenIndiana-discuss] 4k sectors again
> Message-ID:<24488833.81.1329294266564.JavaMail.root at zimbra>
> Content-Type: text/plain; charset=utf-8
>
>>> >  >  Seems most drives are moving to 512-bytes-on-4k-sectors these days,
>>> >  >  as
>>> >  >  with the new 7K4000 drives from Hitachi. I saw a patch for zpool
>>> >  >  some time
>>> >  >  back, fixing ashift, but that's all. Is there an official fix
>>> >  >  somewhere?
>>> >  >  What do people with 4k drives do?
>>> >  >
>> >  
>> >  If the drive reports its block size as 4K ZFS will do the right thing
>> >  already. Only drives that lie about the actual block size and report
>> >  512
>> >  bytes are problematic.
>> >  For such drives the technique I found useful is to create a pool on
>> >  some
>> >  other devices that are true 4K and then replace the devices one by one
>> >  with
>> >  the problematic drives.
>> >  COMSTAR comes really handy for such a trick. Also Linux ZFS let you
>> >  specify
>> >  ashift manually during pool creation.
> Basically,*all*  drives lie about this these days, so we'd better fix it in software instead of hoping drives and politicians stop lying.
>
> So I guess what must be done, then, is to port the fix from Linux ZFS to Illumos/OpenIndiana? Installing this system with linux zfs and then move to openindiana isn't very amusing...
>
> Any idea how much code this is? Or is it the old patch that was rejected a year ago or so?
>
> Vennlige hilsener / Best regards
>
> roy
> --
> Roy Sigurd Karlsbakk
> (+47) 97542685
> roy at karlsbakk.net
> http://blogg.karlsbakk.net/