update-grub help

Dave Howorth dhoworth at mrc-lmb.cam.ac.uk
Tue Jun 1 13:46:39 UTC 2010

Tom H wrote:
> To go back to the OP (who seems to have disappeared)

Hi Tom, thanks for joining in. Hi Goh Lip,

Murphy stepped in right after my last email. My main desktop developed
an intermittent fault that mad it impossible to use so my focus has been
on getting that fixed. Then a public holiday intervened ...

Anyway I did meanwhile start the tests Goh Lip suggested ...

Goh Lip wrote:
> grub> ls (hd5,1)  [write carefully uuid no (do you use label for this?)]
> grub> search -f /boot/vmlinuz- [gives you hd5,1 ?]
> grub> search -f /boot/initrd-  [gives you hd5,1 ?]
> If yes to above, proceed......

And discovered that the problem seems to be somewhere different than
where we've been looking. It seems that the BIOS, and grub, can't see
the disk that SUSE is on, while Ubuntu can. So it's probably time to
describe the machine's hardware a little more.

It has ten disks. The mobo is a Tyan S7010 that has six on-board SATA
ports (ICH10R) that are connected as follows:

#0 - DVD writer
#1 - 500 GB Ubuntu system disk
#2 - 1.5 TB md raid
#3 - 1.5 TB md raid
#4 - 1.5 TB md raid
#5 - 1.5 TB md raid

Then there's a 3ware 9650SE-4LPML with four disks:
- 1.5 TB 3ware raid
- 1.5 TB 3ware raid
- 1.5 TB 3ware raid
- 1.5 TB 3ware raid

And finally there's a plugin PCI-express 2-port SATA card - Belkin
F5U251 with just one disk plugged in:
- 500 GB openSUSE system disk

As far as I can tell, all the hardware is working correctly and
everything works when Ubuntu is running. Also, I believe the 8 disks
connected in RAID arrays are not relevant to this issue so I'm basically
ignoring them. They're presently unused and will just be data stores.

There are some clues in the device.map files. The one produced by running

 sudo grub-mkdevicemap

in Ubuntu looks like this:

(hd0)   /dev/sda
(hd1)   /dev/sdb
(hd2)   /dev/sdc
(hd3)   /dev/sdd
(hd4)   /dev/sde
(hd5)   /dev/sdf
(hd6)   /dev/sdg

which looks like the traditional device.map that is easy to get wrong.
The one in the openSUSE system (not sure what produced it) looks like this:

(hd1)   /dev/disk/by-id/ata-WDC_WD1503FYYS-01T8B0_WD-WMAUR0310828
(hd5)   /dev/disk/by-id/ata-ST31500341AS_9VS3BBQ7
(hd0)   /dev/disk/by-id/ata-Hitachi_HDS721050CLA362_JP1540HN25EWEP
(hd2)   /dev/disk/by-id/ata-ST31500341AS_9VS39AK8
(hd4)   /dev/disk/by-id/scsi-3600050e0e812cc005649000090490000
(hd6)   /dev/disk/by-id/ata-WDC_WD5001AALS-00L3B2_WD-WCASYA878047
(hd3)   /dev/disk/by-id/ata-WDC_WD1503FYYS-01T8B0_WD-WMAUR0310430

which is potentially a whole lot more useful. They both apparently show
the same thing, as viewed from a running Linux system. SEVEN devices:

hd0 sda Ubuntu system disk
hd1 sdb md raid disk
hd2 sdc md raid disk
hd3 sdd md raid disk
hd4 sdg 3ware raid (4 disks)
hd5 sde md raid disk
hd6 sdf openSUSE system disk

Unfortunately, using the ls command in grub only shows SIX devices. hd6
a.k.a sdf a.k.a openSUSE disk, is not there. Checking in the BIOS also
shows only the same six disks.

Now I don't know whether there's some h/w or BIOS configuration needed
(I haven't found any options) or some grub config (google hasn't found
anything) or something completely different?

Cheers, Dave

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