[Tfug] Repairing grub after array rebuild

[Timothy D. Lenz]

Forgot to post back here, got some info on the raid list. Using 
grub-install --recheck /dev/sda seems to have fixed it. I think the 
problem was, device.map needed to be updated to list the correct info 
for the new drive. New version of grub 2 doesn't use device.map, and 
they said it has much better support for raid.

On 3/19/2013 8:57 PM, Kramer Lee wrote:
> It seems that the drive replaced is now designated /dev/md0
>
> a raid designation.
>
> And then grub-install can't find the file system on md0.
>
> I don't know how you are going to boot this, unless you are using a
> live CD/DVD, so you can run
>
> fdisk -l
>
> and see what your disk has as a designation.  hopefully it is /dev/md0
>
> Maybe you can use the Super Grub Boot disk and get up far enough to
> install grub.  Installing grub on a raid array is something I have
> never done.
>
> On 3/11/13, Timothy D. Lenz <tlenz at vorgon.com> wrote:
>> Got the warranty replacement drive installed and got the 3 mirror arrays
>> restored. But the last step I had in my notes to make the drive bootable
>> didn't seem to work. I build raid into the kernel so it can boot right
>> from ether drive if the other fails. My notes from an IRC chat:
>>
>> ---------------------------------------------------------------------
>> [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)
>> [14:05] <Vorg> I haven't added sdb to the array yet, ok, to do this
>> before adding it in?
>> [14:06] <Vorg> sda is the current remaining drive from the array and sdb
>> is the new one. Just don't want to screw up the old one and have nothing
>> working
>> [14:06] <Jordan_U> Vorg: You should add sdb to the array first.
>> ---------------------------------------------------------------------
>>
>> I have done this before, but this time I got some kind of error:
>>
>> ---------------------------------------------------------------------
>> vorg at x64VDR:~$ su
>> Password:
>> x64VDR:/home/vorg# grub-install /dev/sda && grub-install /dev/sdb
>> /usr/sbin/grub-probe: error: no such disk.
>> Auto-detection of a filesystem of /dev/md0 failed.
>> Please report this together with the output of "/usr/sbin/grub-probe
>> --device-map=/boot/grub/devi             ce.map --target=fs -v
>> /boot/grub" to <bug-grub at gnu.org>
>> x64VDR:/home/vorg# exit
>> exit
>> vorg at x64VDR:~$
>> ---------------------------------------------------------------------
>>
>>    The drive replaced is sda.
>>
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>
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