Re: unbelievable, #$@%%!! grub breaks for me AGAIN
On Sat, Jul 24, 2010 at 5:18 PM, <briand@aracnet.com> wrote:
>
> I recovered by editing the grub commands using the 'e' command and by some
> miracle got the thing to ask me what my boot disk is AFTER booting.
> very strange. here's the best part. I gave it the same device grub
> "couldn't find" and the system booted just fine. *##%@$&! grub.
>
> so I'm not sure what I need to provide to have some kind soul help me
> with this, so I'll just describe the problem and maybe somebody can
> tell me what additional info to provide.
>
> the problem, of course, is that it times out and tells me it can't find
> (?) the root filesystem.
>
> I've run update-grub, and it things everything is just hunky dory.
> insert cursing here.
>
> here's the menu entry that DOESN'T WORK (the linux line is wrapped) :
>
> insmod part_msdos
> insmod ext2
> set root='(hd0,msdos2)'
> search --no-floppy --fs-uuid --set a948d6b6-8395-49a1-9f0f-21a10ceee9c2
> linux /boot/vmlinuz-2.6.32-5-amd64 root=UUID=a948d6b6-8395-49a1-9f0f-21a10ceee9c2 ro quiet
> initrd /boot/initrd.img-2.6.32-5-amd64
>
> I have checked the uuid's using "search" from the command line in the booted, working system and it agrees with what grub is using.
>
> I _think_, but am not sure, that when I used 'e' to edit the grub commands I DELETED the search command and replaced the uuid with /dev/sda2 in the linux command.
>
> two things seem odd to me.
>
> 1 /dev/sda2 is a linux partition so what's up with insmod part_msdos and why is set root (hd0, msdos2) ??
>
> 2 why is it insmod'ing ext2 when / is an ext3 filesystem ?
>
> Any help greatly appreciated. I'm going to have to reboot this thing someday, and I'd like to know how to fix this.
>
> more importantly, why does grub not know that it's broken ??!!
The "tells me it can't find (?) the root filesystem" usually happens
once you have gone beyond grub and your initramfs tries to mount and
to switch to your root filesystem.
The "insmod ext2" is for an ext2/ext3/ext4 /boot. ext3 and ext4 can be
thought of as ext2 with extra properties and features...
The "insmod part_msdos" is unusual. I have only ever seen it be added
to grub.cfg for an mdadm'd /boot, but it doesn't hurt. If for some
reason it isn't included in core.img, it helps.
The "(hd0,msdos2)" is new (I have it when I use the latest grub2 in
sid). It seems to be (hd0,2) with the added info that this is a disk
with an msdos partition table.
When I install sid or maverick on a gpt disk, I get "insmod part_gpt"
and "(hd0,gpt2)...
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