[OpenIndiana-discuss] 4k sectors, how to create a root pool with the correct ashift value
Hans J. Albertsson
hans.j.albertsson at branneriet.se
Thu Feb 16 15:55:41 UTC 2012
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
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 Sigurd Karlsbakk
> (+47) 97542685
> roy at karlsbakk.net
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