[TriLUG] Adding SCSI Drive Snuffs GRUB

[Scott Chilcote]

Hi Folks,

I have an Athlon64 system with a single SATA hard drive.  It boots 
Ubuntu Dapper just fine with the default GRUB bootloader.

The system also has an LSI Logic 53c895a SCSI host adapter.  I recently 
tried to plug a new SCSI hard disk into this controller, but when I do, 
the system hangs while booting.  No messages, no GRUB display, just 
"Attempting to Boot from CD-ROM" (which it always does) and then... It 
hangs.

Things that are probably not the reason for this problem:

1. SCSI Device ID Conflict: The device IDs for the 3 devices I have are 
different, as reported by the host adapter at boot time (the other two 
devices are a scanner and a CD-RW drive).

2. SCSI Termination: This is set properly according the the host 
adapter's built in diagnostics.

3. BIOS Hard Drive Boot Priority: I am able to set this in the BIOS.  It 
defaults to the SATA Drive booting first, and the SCSI Drive booting 
second.  I haven't changed it because this seems correct.

4. Drive device assignment by the Linux kernel: I can boot from the 
Ubuntu CD-ROM and open a shell in my usual root partition with both 
drives connected.  When I do, the SATA Disk is /dev/sda, which is 
normal.  The new SCSI drive shows up as /dev/sdb.  This seems right.

I can then use fdisk to list the partition tables on the drives, and 
they are the correct partition tables for the two drives.

The only clue I have for why the boot fails is that there is something 
called the BIOS Device Enumeration Order, and this is not something that 
can be modified using the BIOS configuration.  Apparently this affects 
GRUB at a fundamental level - but I'm having a hard time confirming it 
if so.  I culled this from some postings to forum discussions.

I tried modifying the device IDs in /boot/grub/menu.lst to see if it 
would have any effect.  I made several new list entries for kernels on 
devices like (0,1), (0,2), (1,0), etcetera.  It did not help.  As far as 
I can tell, GRUB isn't running during bootup at all.

I also tried grub-install on /dev/sdb, the SCSI drive.  This had no 
affect either.  There's no evidence that GRUB is loading.

Has anyone run into this problem?  Is there a way to restore GRUB after 
adding this drive, short of doing another Ubuntu install?

Thanks,

Scott C.