Re: error: no such disk

[Michael Evans]

On Fri, Dec 25, 2009 at 9:51 AM, Nick Martin <address@hidden> wrote:
> Changing the lines you mentioned didn't help. I think those lines were
> correct as that section refers to directories on my root partition
> (/dev/sdb4 - hd1,4).
>
> Doing another grub-install with a live cd didn't give any errors either.
>
> 2009/12/24 Tom H <address@hidden>:
>>> I'm having trouble getting grub 2 to work. I've tried installing 2
>>> different distros of Linux (Fedora 12 & Ubuntu 9.10), but grub hasn't
>>> worked on either. I'm getting "error: no such disk", followed by a
>>> grub rescue prompt. When I do "ls" at this prompt, I see this:
>>>
>>> (hd0) (hd0,1) (hd0,2) (hd1,1) (hd1,2) (hd1,3) (hd1,4)
>>>
>>> This seems perfectly reasonable. My setup is as follows:
>>>
>>> 2 ATA hard drives:
>>> /dev/sda (hd0) "master"
>>>    /dev/sda1 (hd0,1) fat32 - Windows XP backup partitionDisk
>>> /dev/sda: 40.0 GB, 40020664320 bytes
>>>    /dev/sda2 (hd0,2) ntfs - Windows XP
>>> /dev/sdb (hd1) "slave"
>>>    /dev/sdb1 (hd1,1) ntfs - storage space
>>>    /dev/sdb2 (hd1,2) ext2 - /boot - 
>>> uuid=d53965e1-bcb1-4158-8531-193af32d52e7
>>>    /dev/sdb3 (hd1,3) swap
>>>    /dev/sdb4 (hd1,4) ext4 - / - uuid=17a9cefd-3754-4048-9aa9-93dc7967a107
>>>
>>> Output from "fdisk -l":
>>>
>>> Disk /dev/sda: 40.0 GB, 40020664320 bytes
>>> 255 heads, 63 sectors/track, 4865 cylinders
>>> Units = cylinders of 16065 * 512 = 8225280 bytes
>>> Disk identifier: 0xe156a499
>>>
>>> Device Boot      Start         End      Blocks   Id  System
>>> /dev/sda1               1         595     4779306    b  W95 FAT32
>>> /dev/sda2   *         596        4865    34298775    7  HPFS/NTFS
>>>
>>> Disk /dev/sdb: 251.0 GB, 251000193024 bytes
>>> 255 heads, 63 sectors/track, 30515 cylinders
>>> Units = cylinders of 16065 * 512 = 8225280 bytes
>>> Disk identifier: 0x43393f15
>>>
>>> Device Boot      Start         End      Blocks   Id  System
>>> /dev/sdb1               1       28684   230400000    7  HPFS/NTFS
>>> /dev/sdb2   *       28685       28708      192780   83  Linux
>>> /dev/sdb3           28709       28890     1461915   82  Linux swap / Solaris
>>> /dev/sdb4           28891       30515    13052812+  83  Linux
>>>
>>> GRUB is installed on the mbr of hd0, which is the drive the BIOS boots
>>> from. I've attached my grub.cfg and device.map file. The device.map
>>> file looks correct to me. At the start of the cfg file, grub seems to
>>> be setting up the graphics, for which it needs a font on /dev/sdb4,
>>> which is ext4. I see it uses insmod ext2. Is this right?
>>>
>>> I've tried to fix the problem with a liveCD by chrooting into those
>>> partitions and doing update-grub, then grub-install /dev/sda. I'm
>>> using GNU GRUB 1.97~beta4.
>>
>> The "set root=(hd1,4)" and "search --no-floppy --fs-uuid --set
>> 17a9cefd-3754-4048-9aa9-93dc7967a107" lines at the top of your
>> grub.cfg are incorrect.
>>
>> They should be "set root=(hd1,2)" and "search --no-floppy --fs-uuid
>> --set d53965e1-bcb1-4158-8531-193af32d52e7" (like within the menuentry
>> entries).
>>
>>
>> _______________________________________________
>> Help-grub mailing list
>> address@hidden
>> http://lists.gnu.org/mailman/listinfo/help-grub
>>
>
>
> _______________________________________________
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> address@hidden
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>

While your thought process is logical the result is not valid.  You
have a separate /boot partition which is the 'root device' for the
grub-files; just as what you see as / after startup is the 'root
device' for your Linux OS.

As specified earlier, you must inform grub of /grub's root device/ not
the /linux root device/.  That would be (hd1,2) in grub2 and (hd1,1)
in grub 0.9x .


### BEGIN /etc/grub.d/10_linux ###
menuentry "Ubuntu, Linux 2.6.31-14-generic" {
        recordfail=1
        if [ -n ${have_grubenv} ]; then save_env recordfail; fi
        set quiet=1
        insmod ext2
        set root=(hd1,2)
        search --no-floppy --fs-uuid --set d53965e1-bcb1-4158-8531-193af32d52e7
        linux   /vmlinuz-2.6.31-14-generic
root=UUID=17a9cefd-3754-4048-9aa9-93dc7967a107 ro   quiet splash
        initrd  /initrd.img-2.6.31-14-generic
}


You'll notice that this section the root device is set to (hd1,2) and
then two files are specified which would be under /boot/ when your
system normally operates; you'll also see that /boot should have a
symlink such that /boot/boot/ has the same files as /boot/ (literally
cd /boot ; ln -s . boot ), this is to aid you, so that you can still
specify /boot/ before files without breaking the install.