Re: Raid failing, which command to remove the bad drive?

["Timothy D. Lenz" <tlenz@vorgon.com>]

On 9/9/2011 3:01 PM, Bill Davidsen wrote:
> Simon Matthews wrote:
>> On Sat, Sep 3, 2011 at 10:03 AM, Simon Matthews
>> <simon.d.matthews@gmail.com> wrote:
>>> On Sat, Sep 3, 2011 at 5:17 AM, Robin Hill<robin@robinhill.me.uk> wrote:
>>>> On Sat Sep 03, 2011 at 04:35:39 -0700, Simon Matthews wrote:
>>>>
>>>>> On Fri, Sep 2, 2011 at 8:42 AM, Timothy D. Lenz<tlenz@vorgon.com>
>>>>> wrote:
>>>>>>> How did you install Grub on the second drive? I have seen some
>>>>>>> instructions on the web that would not allow the system to boot
>>>>>>> if the
>>>>>>> first drive failed or was removed.
>>>>>>>
>>>>>>
>>>>>> I think this is how I did it, at least it is what I had in my notes:
>>>>>>
>>>>>> grub-install /dev/sda&& grub-install /dev/sdb
>>>>>>
>>>>>> And this is from my notes also. It was from an IRC chat. Don't
>>>>>> know if it
>>>>>> was the raid channel or the grub channel:
>>>>>>
>>>>>> [14:02]<Jordan_U> Vorg: No. First, what is the output of grub-install
>>>>>> --version?
>>>>>> [14:02]<Vorg> (GNU GRUB 1.98~20100115-1)
>>>>>> [14:04]<Jordan_U> Vorg: Ok, then run "grub-install /dev/sda&&
>>>>>> grub-install
>>>>>> /dev/sdb" (where sda and sdb are the members of the array)
>>>>>>
>>>>> Which is exactly my point. You installed grub on /dev/sdb such that it
>>>>> would boot off /dev/sdb. But if /dev/sda has failed, on reboot, the
>>>>> hard drive that was /dev/sdb is now /dev/sda, but Grub is still
>>>>> looking for its files on the non-existent /dev/sdb.
>>>>>
>>>> The way I do it is to run grub, then for each drive do:
>>>> device (hd0) /dev/sdX
>>>> root (hd0,0)
>>>> setup (hd0)
>>>>
>>>> That should set up each drive to boot up as the first drive.
>>>>
>>> How about (after installing grub on /dev/sda):
>>> dd if=/dev/sda of=/dev/sdb bs=466 count=1
>> ooops, that should be bs=446, NOT bs=466
>
> Which is why you use grub commands, because a typo can wipe out your
> drive. May or may not have in this case, but there's no reason to do
> stuff like that.
>

Found the problem:

[13:06] <Jordan_U> Vorg: That error is from grub legacy.
[13:08] <Jordan_U> Vorg: Grub2 doesn't use error numbers. "grub error 2" 
is from grub legacy.

I had updated the boot drives to the new Grub. Checked in bios and it 
was set to boot from SATA 3, then SATA 4 AND THEN SATA 1 :(. The second 
pair are data drives and where never ment to have grub.