CentOS - May 2005 - How NOT to have a disk recognized by grub?

Greetings:

I'm upgrading a fileserver running 3.4 (upgrade to a larger disk).  I 
backed up the data from the "old" disk and slapped in a newer, larger 
disk and installed Centos-3.4.  No problems.

Now, there are some files on the "old" disk that I forgot to move to
the
back-up disk, so I'd like to mount the "old" disk as /dev/hdd and
reboot
the system and transfer the files [hdd (old disk) --> hda (new disk)].

However, the old disk still has Grub on the MBR and when I boot, the 
system tries to mount the "/boot" and "/" partitions from
BOTH disks!  I
get errors about duplicate partitions and that those dups won't get 
mounted.The fileserver does boot but with a configuration combination of 
both systems.

Question: Grub is correctly installed and configured on hda.  How do I 
get the boot process to ignore the old disk (and MBR) on hdd???

I tried google but I can't seem to find this fix.

Thanks,

Michael Chinn

this isn't a problem with grub, it's the /etc/fstab configuration most 
likely, you can change the LABEL=/ and LABEL=/boot in the fstab to 
/dev/hda1 or whatever and that should work, or you can boot in rescue mode 
(of the installation CD) and relabel the extra disk

On Fri, 20 May 2005, Michael wrote:
> Greetings:
>
> I'm upgrading a fileserver running 3.4 (upgrade to a larger disk).  I
backed
> up the data from the "old" disk and slapped in a newer, larger
disk and
> installed Centos-3.4.  No problems.
>
> Now, there are some files on the "old" disk that I forgot to move
to the
> back-up disk, so I'd like to mount the "old" disk as /dev/hdd
and reboot the
> system and transfer the files [hdd (old disk) --> hda (new disk)].
>
> However, the old disk still has Grub on the MBR and when I boot, the system
> tries to mount the "/boot" and "/" partitions from BOTH
disks!  I get errors
> about duplicate partitions and that those dups won't get mounted.The 
> fileserver does boot but with a configuration combination of both systems.
>
> Question: Grub is correctly installed and configured on hda.  How do I get 
> the boot process to ignore the old disk (and MBR) on hdd???
>
> I tried google but I can't seem to find this fix.
>
> Thanks,
>
> Michael Chinn
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos
>

On Fri, May 20, 2005 12:01 pm, Michael said:
> Greetings:
>
> I'm upgrading a fileserver running 3.4 (upgrade to a larger disk).  I
> backed up the data from the "old" disk and slapped in a newer,
larger
> disk and installed Centos-3.4.  No problems.
>
> Now, there are some files on the "old" disk that I forgot to move
to the
> back-up disk, so I'd like to mount the "old" disk as /dev/hdd
and reboot
> the system and transfer the files [hdd (old disk) --> hda (new disk)].
>
> However, the old disk still has Grub on the MBR and when I boot, the
> system tries to mount the "/boot" and "/" partitions
from BOTH disks!  I
> get errors about duplicate partitions and that those dups won't get
> mounted.The fileserver does boot but with a configuration combination of
> both systems.
>
> Question: Grub is correctly installed and configured on hda.  How do I
> get the boot process to ignore the old disk (and MBR) on hdd???
>
> I tried google but I can't seem to find this fix.
Is it possible that the old disk and the new one have the same label name?

That is the only reason I could think of why it would try to mount or
confuse the disks.

If that is the problem, you can boot via CD-1 and use "linux rescue"
then
relabel the hdd disk to something else using the command:

e2label /dev/hdd#
e2label /dev/hda#

If they are the same ... relabel hdd with the command:

e2label /dev/hdd# new_name

(the # is the specific partition number)
-- 
Johnny Hughes
<http://www.HughesJR.com/>

Michael wrote:
> Greetings:
> 
> I'm upgrading a fileserver running 3.4 (upgrade to a larger disk).  I 
> backed up the data from the "old" disk and slapped in a newer,
larger
> disk and installed Centos-3.4.  No problems.
> 
> Now, there are some files on the "old" disk that I forgot to move
to the
> back-up disk, so I'd like to mount the "old" disk as /dev/hdd
and reboot
> the system and transfer the files [hdd (old disk) --> hda (new disk)].
> 
> However, the old disk still has Grub on the MBR and when I boot, the 
> system tries to mount the "/boot" and "/" partitions
from BOTH disks!  I
> get errors about duplicate partitions and that those dups won't get 
> mounted.The fileserver does boot but with a configuration combination of 
> both systems.
> 
> Question: Grub is correctly installed and configured on hda.  How do I 
> get the boot process to ignore the old disk (and MBR) on hdd???
> 
> I tried google but I can't seem to find this fix.
You have several problems here with various things.  Not just the Grub.

First, are you sure BIOS is booting the right disk?  If yes, it should 
load Grub from correct MBR.

Second, you can select which disk Grub will use by modifying "root 
(hd0,0)" (or whatever numbers are in your config file).  That way, 
correct kernel and initrd will be loaded.  Also make sure root option in 
kernel line points to correct root partition.

Third, what is in your /etc/fstab file?  If you are using labels, and 
they are not uniq, you have problem.  The easy way aruond it is to wipe 
out file system labels from old partitions.  For example in Rescue mode:

# e2label /dev/hdd0 ""

(giving the empty string will wipe out the label).

Fourth, if your boot disk is not at the same device name as when you 
installed the system, you'll need to rebuild initrd image.  From what 
you described you haven't moved the new disk, so most likely you don't 
need to do this.  Also, if you moved disks around, you might need to 
reinstall Grub (probably not applicable in your case).

-- 
Aleksandar Milivojevic <amilivojevic at pbl.ca>    Pollard Banknote
Limited
Systems Administrator                           1499 Buffalo Place
Tel: (204) 474-2323 ext 276                     Winnipeg, MB  R3T 1L7