From: Peter Rabbitson <rabbit+list@rabbit.us>
To: Bill Davidsen <davidsen@tmr.com>
Cc: Richard Scobie <richard@sauce.co.nz>,
Linux RAID Mailing List <linux-raid@vger.kernel.org>
Subject: Re: RAID 1 and grub
Date: Sun, 03 Feb 2008 16:26:23 +0100 [thread overview]
Message-ID: <47A5DD1F.4010306@rabbit.us> (raw)
In-Reply-To: <47A5E04E.4050403@tmr.com>
Bill Davidsen wrote:
> Richard Scobie wrote:
>> A followup for the archives:
>>
>> I found this document very useful:
>>
>> http://lists.us.dell.com/pipermail/linux-poweredge/2003-July/008898.html
>>
>> After modifying my grub.conf to refer to (hd0,0), reinstalling grub on
>> hdc with:
>>
>> grub> device (hd0) /dev/hdc
>>
>> grub> root (hd0,0)
>>
>> grub> (hd0)
>>
>> and rebooting with the bios set to boot off hdc, everything burst back
>> into life.
>>
>> I shall now be checking all my Fedora/Centos RAID1 installs for grub
>> installed on both drives.
>
> Have you actually tested this by removing the first hd and booting?
> Depending on the BIOS I believe that the fallback drive will be called
> hdc by the BIOS but will be hdd in the system. That was with RHEL3, but
> worth testing.
>
The line:
grub> device (hd0) /dev/hdc
simply means "treat /dev/hdc as the first _bios_ hard disk in the system".
This way when grub writes to the MBR of hd0, it will be in fact writing to
/dev/hdc. The reason the drive must be referenced as hd0 (and not hd2) is
because grub enuerates drives according to the bios, and therefore the drive
from which the bios is currently booting is _always_ hd0.
next prev parent reply other threads:[~2008-02-03 15:26 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-30 22:06 RAID 1 and grub Richard Scobie
2008-01-31 0:41 ` David Rees
2008-01-31 1:37 ` Richard Scobie
2008-01-31 2:33 ` Richard Scobie
2008-01-31 2:47 ` David Rees
2008-01-31 3:06 ` Richard Scobie
2008-01-31 17:51 ` David Greaves
2008-02-02 23:51 ` Keld Jørn Simonsen
2008-02-03 3:50 ` Richard Scobie
2008-02-03 15:39 ` Bill Davidsen
2008-02-03 15:26 ` Peter Rabbitson [this message]
2008-02-03 18:31 ` Richard Scobie
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