[CentOS] Re: Replacing failed software RAID drive

[Les Mikesell]

Tony Mountifield wrote:

>>> 2. Can a install grub on the replaced boot drive with the system still
>>>    running?
>> Yes, after the /boot partition re-sync has completed, execute grub and:
>>
>> root (hd0,0)
>> setup (hd0)
> 
> And also:
> 
> root (hd1,0)
> setup (hd1)
> 
>> quit
> 
> That will ensure both mirrored drives have GRUB in the MBR (the MBR isn't
> mirrored, only partitions are). Otherwise if hd0 fails, the system will
> be unable to boot from the good drive hd1.
> 
> See http://fedoranews.org/mediawiki/index.php/How_to_setup_and_manage_your_disk_software_mirroring

Earlier in the thread, the OP said the 2nd mirror is on sde, not sdb, so 
this won't work for him and depending on his scsi controller, probably 
can't boot from that drive at all.  In any case it is a good idea to 
know how to do a rescue mode boot from your install CD.

-- 
   Les Mikesell
    lesmikesell at gmail.com