[plug] grub query in mixed sata / pata setup

Tomasz Grzegurzko tomasz89 at gmail.com
Thu Aug 2 11:02:57 WST 2007

On 8/2/07, Denis Brown <dsbrown at cyllene.uwa.edu.au> wrote:
> Hello PLUG list members,
> Not totally sure if this is sata / pata related but here goes...
> ASUS P5K mobo with sata controller within the Intel P35 chipset
> (Northbridge, from what I can infer) and a JMicron JMB363 device providing
> pata and other services.   Disk setup is three 300GB sata which will be
> software RAID5'ed to provide the data store and an 80GB pata drive intended
> for system use.   Also pata CD/DVD-RW.
> The CD is connected as master, the 80GB drive as slave (I think it odd, but
> if I change that to HDD master and CD slave it will not see or boot from
> the CD.)
> Ubuntu (7.0.4 for 64-bit) installs on the 80GB drive and determines that it
> is /dev/sdd    The three to-be-RAIDed's are /dev/sda, sdb and
> sdc.    Attempt to boot from the HDD yields error 17 "Cannot mount selected
> partition" from GRUB.
> But... I activated the boot choice menu screen for Grub and it appears -
> ergo the path /boot/grub *is* being found.   Further, if I drop into Grub's
> shell (the "c" key from the boot choice menu) I can do a cat
> /boot/grub/menu.lst for example and find the contents as I expect them.   I
> can also successfully see the contents of fstab with a cat /etc/fstab
> So, what's its problem about not being able to mount the partition????
> May not be related... initially I was getting Grub error 5 and eliminated
> this by fdisk'ing the three data drives to create a partition on
> each.    Hmmm... maybe I should format them to something (ext3 for example)
> just in case Grub is trying to mount one of them.   But why would
> it?   Nothing in the Ubuntu installation talked about setting up the data
> drives.
> Hitting with clue-bat appreciated :-)
> Denis

I'm assuming you're trying to run/boot from grub which resides on a RAID 5.

It's a partitioning/filesystem problem. GRUB doesn't understand RAID5,
only ext2, fat, reiser, and RAID1. I had to set up a system a while
ago and ended up partitioning a RAID1 for /boot formatted as ext2.
Google for grub + raid and you'll see what I mean.

Otherwise, the problem is in the root (hd0,0) or whatever clause. You
may need to modify this as the BIOS assumes that the root device is
nearly always hd0,0 but this is not always deterministic.


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