da...@kenpro.com.au wrote:
"david" == david <da...@kenpro.com.au> writes:
On 26/01/10 23:25, da...@kenpro.com.au wrote:
After doing a routine reboot I get grub error 15 on Ubuntu 8.10
Does this error occur before or after the GRUB menu appears?
i.e. do you get presented with a menu to select which kernel at
all, or does it bomb out before it gets to that stage?
When I enter the BIOS I am only getting one option for booting
into a hard-drive, although I recollect that previously I had to
select which hard drive.
The BIOS does recognise all three hard drives as being present. I
am able to mount the bootable drive from a live CD and the data
appears to be OK.
Any suggestions what has gone amiss?
It may well be that the GRUB MBR is simply looking at the wrong
drive for the menu.lst file. In which case, re-running grub-install
would be my first suggestion as a fix.
david> It bombs before the kernel list. I've tried running:
david> #grub-install /dev/sdc Could not find device for /boot: Not
david> found or not a block device.
Hmmm. This sounds as if the mapping from BIOS to Linux drives is
broken.
Try grub-install with the --recheck option.
The plot thickens .....
# grub-install --recheck /dev/sdc3
Could not find device for /boot: Not found or not a block device
I unplugged all but the root drive and it boots perfectly. Progressively
replugging all the drives seems to have random results. There is one IDE
drive and three SATA, one of which is the rood drive and another one is in
a caddy. I have had as many as two of the four extra drives running but
can't get them all to go at once.
I'm beginning to think it's a BIOS/motherboard problem.
I've just rebooted again with only the boot drive plugged in.
I'll wager you have the grub MBR sitting on one of your other drives
and the bios (as most do) randomly changes the boot order when you add
new drives, so having that one in a caddy will mess with things.
when it decides to boot off the one with the other grub you get an error.
you can zero it if you want and see if that helps
backup first
dd if=/dev/hda of=/mbrbackup.bin bs=512 count=1
then zero
dd if=/dev/zero of=/dev/hda bs=446 count=1
note the 446 bytes, if you do 512 it'll wipe the partition table (which
is a bad thing)
if your lucky that'll be enough that the bios will skip those when it
comes to boot time.
make sure your fstab is all done by uuid not path because that will
probably change as you add and remove drives or the phase of the moon
changes.
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