[CentOS] Replacing failed software RAID drive

Wed Oct 10 03:21:24 UTC 2007
Clint Dilks <clintd at scms.waikato.ac.nz>

Hugh E Cruickshank wrote:
> From: Les Mikesell Sent: October 7, 2007 18:53
>   
>> OK, you just have to replace the drive, fdisk matching partitions on it 
>> ("fdisk -l /dev/sde" will show the sizes you need), then use
>> mdadm --add /dev/md? /dev/sda?
>> for each one to add the missing partition back.
>>     
>
> I have been able to review all this and it looks very straight forward.
>
>   
>> Then reinstall grub on the drive.
>>     
>
> Now I have some questions:
>
> 1. Since the /boot partition was mirrored and will be restored on the
>    new sda drive I do not really want to do a full grub install. From
>    what I have read that will overwrite existing /boot/grub/grub.conf
>    file. So I just want to write the MBR on the drive. How to I do
>    that (the docs I have found were rather unclear on that aspect)?
>
>   

Boot the system from CD or similar in Rescue Mode and then use something 
like

grub-install --no-floppy /dev/hda



> 2. Can a install grub on the replaced boot drive with the system still
>    running?
>
> TIA
>
> Regards, Hugh
>
>   
Yes