[CentOS] Make Raid1 2nd disk bootable?

Les Mikesell lesmikesell at gmail.com
Wed May 16 02:45:41 UTC 2007


Mike Fedyk wrote:

>> On earlier versions of Centos, I could boot the install CD in rescue 
>> mode, let it find and mount the installed system on the HD even when 
>> it was just one disk of RAID1 partitions (type=FD).   When booting 
>> from the centos5 disk the attempt find the system gives a box that 
>> says 'You don't have any Linux partitions'.  At the bottom of the 
>> screen there is something that says:
>>  cl->raidtype=5 rd_type=1
>> <TAB><Alt-Tab> between elements cl->raidtype=5 rd_type=1 <F12> next 
>> screen
>> But there is no way to access the bottom part.  If I hit the OK button 
>> and get a shell I can mount the partitions myself, but then when I 
>> chroot to the mounted system there are no devices in /dev.  What's the 
>> right way to install grub on what was /dev/sdb in the original install 
>> but is now the only disk and moved to /dev/sda?  The old /dev/sda is 
>> no longer there....

 > The right way is to boot directly into grub and ask it to find the
 > stage1 file on the partitions.

If grub had been there it should have found it itself - but it wasn't so 
I had to boot the CD.

 > Then set your root partition

I was able to do the install from the rescue mode boot, but only because 
the /boot partition was all still intact and I only had to use the setup 
command in grub.

 > Then setup grub on the mbr of each drive.

There was only on drive at that point.  It's syncing to a new mirror now.


 > There are many pages google can find with explicit details.

Grub isn't so much the issue here as the difference in the rescue mode 
boot.  I'm used to being able to boot the CD, chroot into the existing 
system and have pretty much normal access regardless of what was broken. 
Now that the system /dev directory is basically empty, things don't work 
  when you have to mount the partitions manually.  Is there a step to 
set up devices so the chroot will work?

-- 
   Les Mikesell
     lesmikesell at gmail.com




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