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Date: Tue, 26 May 2009 19:29:00 +0300
From: Andriy Gapon <avg@icyb.net.ua>
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Cc: FreeBSD Stable Mailing List <freebsd-stable@freebsd.org>
Subject: Re: ZFS boot on zfs mirror
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on 26/05/2009 19:21 George Hartzell said the following:
> Dmitry Morozovsky writes:
>  > On Tue, 26 May 2009, Mickael MAILLOT wrote:
>  > 
>  > MM> Hi,
>  > MM> 
>  > MM> i prefere use zfsboot boot sector, an example is better than a long talk:
>  > MM> 
>  > MM> $ zpool create tank mirror ad4 ad6
>  > MM> $ zpool export tank
>  > MM> $ dd if=/boot/zfsboot of=/dev/ad4 bs=512 count=1
>  > MM> $ dd if=/boot/zfsboot of=/dev/ad6 bs=512 count=1
>  > MM> $ dd if=/boot/zfsboot of=/dev/ad4 bs=512 skeep=1  seek=1024
>  > MM> $ dd if=/boot/zfsboot of=/dev/ad6 bs=512 skeep=1  seek=1024
>  > 
>  > s/skeep/skip/ ? ;-)
> 
> What is the reason for copying zfsboot one bit at a time, as opposed
> to 
> 
>   dd if=/boot/zfsboot of=/dev/ad4 bs=512 count=2

seek=1024 for the second part? and no 'count=1' for it? :-)

[Just guessing] Apparently the first block of zfsboot is some form of MBR and the
rest is zfs-specific code that goes to magical sector 1024.

-- 
Andriy Gapon