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In-Reply-To: <4E4D50CD.5080806@rawbw.com>
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Date: Fri, 19 Aug 2011 11:15:30 +0100
Message-ID: <CAFHbX1K+RuzBKouAbN0+SCOSAkGNdgMzC92YN7GeKn_pD=J=tg@mail.gmail.com>
From: Tom Evans <tevans.uk@googlemail.com>
To: Yuri <yuri@rawbw.com>
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Cc: freebsd-hackers@freebsd.org
Subject: Re: ZFS installs on HD with 4k physical blocks without any warning
 as on 512 block size device
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On Thu, Aug 18, 2011 at 6:50 PM, Yuri <yuri@rawbw.com> wrote:
> Some latest hard drives have logical sectors of 512 byte when they actually
> have 4k physical sectors. Here is the document describing what to do in such
> case:
> http://ivoras.net/blog/tree/2011-01-01.freebsd-on-4k-sector-drives.html .
> For UFS: newfs -U -f 4096 /dev/da0
> For ZFS: gnop create -S 4096 /dev/da0 && zpool create data /dev/da0.nop
>
> I am sure most people just install such hard drive without doing this and
> potentially get suboptimal performance since they aren't aware about this.
> Shouldn't UFS and ZFS drivers be able to either read the right sector size
> from the underlying device or at least issue a warning?
>
> Yuri

The device never reports the actual sector size, so unless FreeBSD
keeps a database of 4k sector hard drives that report as 512 byte
sector hard drives, there is nothing that can be done.

Cheers

Tom