Replacing disk in Linux Software RAID 1

[jludwig]

On Wed, 2004-08-18 at 10:19, Robin Laing wrote:
> 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
If I remember correctly grub can be on both and chain loaded, but, if
your first drive has issues and can't start grub you're dead.
-- 
jludwig <wralphie at comcast.net>