Hello everyone!

I had a hard drive die on me last week, and during the recovery
process the MBR got wiped. During system boot, I now get the
infamous "GRUB" message immediately before the system hangs.

The system is a dual processor Pentium IV Xeon machine dual
booting between Redhat 9.0 (fully updated via RHN, including
kernel 2.4.20-28.9smp) and Windows 2000 Professional. The system
has a mix of IDE and SCSI drives, as shown by the annotated
/boot/grub/device.map file shown below:

# this device map was generated by anaconda
(fd0) /dev/fd0
(hd0) /dev/hda --> Windows 2000 disk
(hd1) /dev/sda --> RH 9 system disk
(hd2) /dev/sdb --> RH 9 user disk 1
(hd3) /dev/sdc --> RH 9 user disk 2


The 1st SCSI disk is divided as follows:
/dev/sda1 --> /boot
/dev/sda2 --> /


The /MBR was wiped via fdisk (DOS version) and then Windows was
reinstalled. I don't have a boot floppy (dumb, I know) and my
attempts to use grub or grub-install from the RH 9 install DVD
have been unsuccessful. I either get the same "GRUB" message
followed by the hung system, or an "ERROR 15: File not Found".
Keep in mind that when using the DVD in rescue mode, all the
other drives are mounted under /mnt/sysimage. Thus, the system
/boot location and the hard-coded paths in grub-install are
incorrect.


The exact grub commands that I tried were (after grub-install
failed) were:

grub> root (hd1,0)
grub> setup (hd0)
grub> quit

So what did I miss, and what do I need to do differently since I
am working from the RH 9 install CD's/DVD in rescue mode instead
of a true boot floppy?

Many thanks for any pointers!

-Brian

BTW, does anyone know of a place to download various boot floppies?
I didn't find anything after several google attempts...

jonesbr@sbcglobal.net wrote:
>
> The /MBR was wiped via fdisk (DOS version) and then Windows was
> reinstalled. I don't have a boot floppy (dumb, I know) and my
> attempts to use grub or grub-install from the RH 9 install DVD
> have been unsuccessful. I either get the same "GRUB" message
> followed by the hung system, or an "ERROR 15: File not Found".
> Keep in mind that when using the DVD in rescue mode, all the
> other drives are mounted under /mnt/sysimage. Thus, the system
> /boot location and the hard-coded paths in grub-install are
> incorrect.
>
>
> The exact grub commands that I tried were (after grub-install
> failed) were:
>
> grub> root (hd1,0)
> grub> setup (hd0)
> grub> quit
>
> So what did I miss, and what do I need to do differently since I
> am working from the RH 9 install CD's/DVD in rescue mode instead
> of a true boot floppy?
>
> Many thanks for any pointers!

Did you chroot into /mnt/sysimage before trying to install grub
to the MBR again?

--
Confucius: He who play in root, eventually kill tree.
Registered with The Linux Counter. http://counter.li.org/
Slackware 9.1.0 Kernel 2.4.24 SMP i686 (GCC) 3.3.2
Uptime: 42 days, 11:17, 1 user, load average: 0.00, 0.00, 0.00

David wrote:
> jonesbr@sbcglobal.net wrote:
>
>>
>> The /MBR was wiped via fdisk (DOS version) and then Windows was
>> reinstalled. I don't have a boot floppy (dumb, I know) and my
>> attempts to use grub or grub-install from the RH 9 install DVD
>> have been unsuccessful. I either get the same "GRUB" message
>> followed by the hung system, or an "ERROR 15: File not Found".
>> Keep in mind that when using the DVD in rescue mode, all the
>> other drives are mounted under /mnt/sysimage. Thus, the system
>> /boot location and the hard-coded paths in grub-install are
>> incorrect.
>>
>>
>> The exact grub commands that I tried were (after grub-install
>> failed) were:
>>
>> grub> root (hd1,0)
>> grub> setup (hd0)
>> grub> quit
>>
>> So what did I miss, and what do I need to do differently since I
>> am working from the RH 9 install CD's/DVD in rescue mode instead
>> of a true boot floppy?
>>
>> Many thanks for any pointers!
>
>
> Did you chroot into /mnt/sysimage before trying to install grub to the
> MBR again?

Yep, did that. Good thought though - thanks!

-Brian

jonesbr@sbcglobal.net wrote:
> David wrote:
>>
>> Did you chroot into /mnt/sysimage before trying to install grub to the
>> MBR again?
>
> Yep, did that. Good thought though - thanks!

Ok I think I see what may be the problem. Boot with the rescue CD
and edit the grub config file the section shown below.

grub> root (hd1,0) <<< This would be /dev/sdb1
I think you need (hd0,1) if root is /dev/sda2
grub> setup (hd0)
grub> quit

--
Confucius: He who play in root, eventually kill tree.
Registered with The Linux Counter. http://counter.li.org/
Slackware 9.1.0 Kernel 2.4.24 SMP i686 (GCC) 3.3.2
Uptime: 42 days, 12:32, 1 user, load average: 0.21, 0.13, 0.12

jonesbr@sbcglobal.net wrote:

>> Did you chroot into /mnt/sysimage before trying to install grub to the
>> MBR again?
>
> Yep, did that. Good thought though - thanks!

Make sure you chroot correctly. After a correct chroot a 'ls /boot' will
give you your original boot file system. For original file systems mounted
under /mnt/sysimage (e. g. /mnt/sysimage/etc) the command is
'cd /mnt/sysimage' followed by 'chroot .'

On a correctly chrooted system grub-install should *not* fail.

Also, make sure the entry in the grub.conf on the mounted file system points
to the correct disk, (hd1,0) in your case.

Joerg

--
OpenPGP: D14F 2782 1276 EBB4 E4E3 0BF1 838D DD4C EB56 1C99

David wrote:
> jonesbr@sbcglobal.net wrote:
>
>> David wrote:
>>
>>> Did you chroot into /mnt/sysimage before trying to install grub to
>>> the MBR again?
>>
>> Yep, did that. Good thought though - thanks!
>
>
> Ok I think I see what may be the problem. Boot with the rescue CD and
> edit the grub config file the section shown below.
>
> grub> root (hd1,0) <<< This would be /dev/sdb1
> I think you need (hd0,1) if root is /dev/sda2

But in my case, the first (and only) IDE drive at /dev/hda
would be (hd0), correct? The first SCSI drive, /dev/sda,
would be (hd1).

Again, my device.map, after some marking up (i.e. all :

# this device map was generated by anaconda
(fd0) /dev/fd0
(hd0) /dev/hda --> Windows 2000 disk
(hd1) /dev/sda --> RH 9 system disk
(hd2) /dev/sdb --> RH 9 user disk 1
(hd3) /dev/sdc --> RH 9 user disk 2


Also remember that I have /dev/sda divided up like so
(per default Redhat 9 install):

/dev/sda1 --> /boot
/dev/sda2 --> /


> grub> setup (hd0)
> grub> quit

Grub is the only bootloader on the machine (no lilo, no
Windows bootloader). Thus, grub's root (hd1,0) command
should put the grub files in /boot, and the setup (hd0)
command should install grub in the MBR, correct?

I thought I had that much figured out...

Thanks for the help!

-Brian

Joerg Sauer wrote:
> jonesbr@sbcglobal.net wrote:
>
>
>>>Did you chroot into /mnt/sysimage before trying to install grub to the
>>>MBR again?
>>
>>Yep, did that. Good thought though - thanks!
>
>
> Make sure you chroot correctly. After a correct chroot a 'ls /boot' will
> give you your original boot file system. For original file systems mounted
> under /mnt/sysimage (e. g. /mnt/sysimage/etc) the command is
> 'cd /mnt/sysimage' followed by 'chroot .'
>
> On a correctly chrooted system grub-install should *not* fail.

I thought so too! I did exit out of chroot session once when
I was typing too fast, but the other times I made sure that I
issued the "chroot /mnt/sysimage" as soon as I got the command
line and worked from there.

I haven't messed with grub-install much (compared to the grub
commandline), so I guess I need to verify how it works. i.e.
"grub-install --root-directory=/boot /dev/hda" would be the
proper command in this case, since the /dev/hda is the first
drive seen by the BIOS, and I have /boot on a separate partition
on the first SCSI drive, correct?


> Also, make sure the entry in the grub.conf on the mounted file system points
> to the correct disk, (hd1,0) in your case.

Another good check... I thought I verified this, but I'll double
check. (I'm not at the machine at the moment.)


> Joerg

Thanks for the suggestions!

-Brian

jonesbr@sbcglobal.net wrote:

> I haven't messed with grub-install much (compared to the grub
> commandline), so I guess I need to verify how it works.

Using the GRUB command line is perfectly OK and the commands you gave seem
correct to me. I just thought that the problem might be related to file
system references (possibly resulting from lack of chroot) since you
mentioned that grub-install had failed.

A useful GRUB command you might try if you haven't already is 'find
<filename>' which tells you on which drive and partition a particular file
resides, in GRUB nomenclature.

Anyway, if GRUB is configured correctly and the system still does not boot,
there might be a drive enumeration issue. I have seen reports of cases
where drives were enumerated by the BIOS differently than by the OS after
it had loaded.

Since you have many drives on more than one controller something like that
might be happening. I'm going way out on a limb there, though...

But just to make sure... I think that standard DOS or Windows FDISK will
always show drives in the same order that they are referenced by the BIOS,
so that might be a way to check if any drives are enumerated differently by
the BIOS than after booting from the Red Hat recovery DVD.

Joerg

--
OpenPGP: D14F 2782 1276 EBB4 E4E3 0BF1 838D DD4C EB56 1C99

On Tue, 17 Feb 2004 05:03:01 +0000, jonesbr wrote:

> Hello everyone!
>
> I had a hard drive die on me last week, and during the recovery
> process the MBR got wiped. During system boot, I now get the
> infamous "GRUB" message immediately before the system hangs.
>
> <snip>
>
> The /MBR was wiped via fdisk (DOS version) and then Windows was
> reinstalled. I don't have a boot floppy (dumb, I know) and my
> attempts to use grub or grub-install from the RH 9 install DVD
> have been unsuccessful. I either get the same "GRUB" message
> followed by the hung system, or an "ERROR 15: File not Found".
> Keep in mind that when using the DVD in rescue mode, all the
> other drives are mounted under /mnt/sysimage. Thus, the system
> /boot location and the hard-coded paths in grub-install are
> incorrect.
>
>
> The exact grub commands that I tried were (after grub-install
> failed) were:
>
> grub> root (hd1,0)
> grub> setup (hd0)
> grub> quit
>
> So what did I miss, and what do I need to do differently since I
> am working from the RH 9 install CD's/DVD in rescue mode instead
> of a true boot floppy?
>
> Many thanks for any pointers!
>
> -Brian
>
> BTW, does anyone know of a place to download various boot floppies?
I don't think there is any such thing for linux (too many variables).
> I didn't find anything after several google attempts...
>
Good things...
1. Partition table not damaged. DOS's fdisk just changes loader code.
2. Rescue mode on CD available.
3. Grub command shell working.

Okay...
When you run the grub shell,
grub> setup (hd0)

are any errors issued about missing files? You must be able to
find all the necessary files in this environment. Otherwise, they won't
be correctly linked and written as part of the setup. This step must
succeed before boot will work from the hard disk.

You could make a boot floppy in the rescue environment. Then fix your
loader once your system is booted normally from the floppy.

--
Wonderful what we can do nowadays.
http://us.imdb.com/title/tt0085959/quotes

jonesbr@sbcglobal.net wrote:
>
> I thought I had that much figured out...

I hadn't noticed you had a system with mixed IDE and SCSI drives.
I find lilo much easier to deal with than grub.

--
Confucius: He who play in root, eventually kill tree.
Registered with The Linux Counter. http://counter.li.org/
Slackware 9.1.0 Kernel 2.4.24 SMP i686 (GCC) 3.3.3
Uptime: 42 days, 22:02, 2 users, load average: 0.46, 0.24, 0.1