Replacing disk in Linux Software RAID 1

[Robin Laing]

jludwig wrote:
> On Tue, 2004-08-17 at 11:26, Robin Laing wrote:
> 
>>Michael Mansour wrote:
>>
>>>Hi Robin,
>>>
>>>
>>>>Would it be possible to write the MBR to the second
>>>>disk just in case?
>>>>-- 
>>>>Robin Laing
>>>
>>>
>>>Yes, I've tested this by removing the first drive and
>>>writing grub to the MBR of the second drive and it did
>>>work fine, although when putting the first drive back
>>>in there then I had the issue with two MBR's which got
>>>things a little confused.
>>>
>>>Basically, what I learnt from that saga is that grub
>>>should only reside on one drive.
>>>
>>>Michael.
>>>
>>
>>I for one when I was a system admin, did not like getting called in at 
>>03:00 due to a crash.  And doesn't always seem to happen at 03:00 when 
>>things go bad?  :)
>>
>>I feel it should be there.  Now if you do write it to the second disk 
>>and you have problems, this could be a problem.
>>
>>-- 
>>Robin Laing
> 
> Many newer BIOS' will allow for booting off of a secondary drive.
> 
> If this is the case with your machine I would just load the second drive
> where it sits and just change the BIOS setting if necessary.
> 
> (I used to do this with SCSI and IDE for a duel boot system.)
> 

This isn't the issue.

As stated by Michael, having Grub on the second drive caused problems. 
  My point was in a situation where your /boot is actually part of a 
Raid array, and the second drive "cannot have Grub on it" then it 
isn't much use in an emergency as you will have to have a copy of the 
MBR to update your second drive.

Is this an issue with RAID or Grub or the Bios?

-- 
Robin Laing