GRUB2 booting with labels (no UUID)

[MountainX]

I cannot fully express my gratitude for your help with this! Thank you!

I will try it and report back.

BTW, I have already verified that my hand-edited menu stanza works. I edited grub.cfg and I've been booting up with it for a couple days. But I will proceed carefully, following your advice. (And I am also working on a test machine atm that contains no data.)

[MountainX]

It looks like this approach works
I'm still testing, but so far so good. I had to make a few minor changes in the executable portion. I'll post that when I'm done. (It's on another machine, so I can't post it now.)

It looks like we can also edit grub-mkconfig_lib to generate a search line similar to this using your suggestion above

echo "search --no-floppy --label ${auto_label} --set root"

I think I have it working...

[MountainX]

Thanks drs305. It works!

It would be great if the moderators could split this thread starting at post #8. At that point the conversation turned to using labels with grub2. This is an important question I think. I have seen a lot of people asking about it and I have not found a good solution yet. But the approach drs305 suggested does work. So it would be nice to have it in a new thread with a proper title that reflects grub2 and labels.

Let me summarize what I did. I hope others comment in regard to whether all these steps are necessary and accurate. But this IS WORKING for me.

1. changed /etc/defaults/grub
uncommented this line and used quotes around true:

GRUB_DISABLE_LINUX_UUID="true"

2. changed /etc/grub.d/10_linux as follows:

auto_label="`e2label ${GRUB_DEVICE_BOOT} 2>/dev/null`"
  linux_root_device_thisversion="LABEL=${auto_label}"
  cat << EOF
	linux	${rel_dirname}/${basename} root=${linux_root_device_thisversion} ro ${args}
EOF

3. changed /usr/lib/grub/grub-mkconfig_lib as follows. I know this code could be improved by including it in a proper conditional, but I didn't know how to do that. So it just executes always.

  # If there's a filesystem UUID that GRUB is capable of identifying, use it;
  # otherwise set root as per value in device.map.
  echo "set root='`${grub_probe} --device ${device} --target=drive`'"
  #if fs_label="`${grub_probe} --device ${device} --target=fs_uuid 2> /dev/null`" ; then
    #echo "search --no-floppy --fs-uuid --set ${fs_uuid}"
  #fi
auto_label="`e2label ${device} 2>/dev/null`"
echo "search --no-floppy --label ${auto_label} --set root"

Those changes generate perfect (as far as I'm concerned) stanzas in grub.cfg. And my test machine boots as expected.

menuentry "Linux Mint 9, 2.6.32-21-generic (/dev/sda1) -- recovery mode" --class linuxmint --class gnu-linux --class gnu --class os {
	recordfail
	insmod ext2
	set root='(hd0,1)'
	search --no-floppy --label my_label --set root
	echo	'Loading Linux 2.6.32-21-generic ...'
	linux	/boot/vmlinuz-2.6.32-21-generic root=LABEL=my_label ro single 
	echo	'Loading initial ramdisk ...'
	initrd	/boot/initrd.img-2.6.32-21-generic
}

my /etc/fstab also uses labels. Here's an example (although this exact example is from another machine)

LABEL=home_volume       /home   ext4    noatime,acl,user_xattr 1 2
LABEL=root_volume       /       ext4    noatime,acl,user_xattr 1 1
LABEL=swap_volume       swap    swap    defaults 0 0
LABEL=boot_volume       /boot   ext2    noatime,acl 1 2

[drs305]

Thanks drs305. It works!

It would be great if the moderators could split this thread starting at post #8.

MountainX,

As you can see, I've split the thread and created this new one specifically for your "label" issues.

You may need to resubscribe to your original post:
http://ubuntuforums.org/showthread.php?t=1529799

[hotdoog]

This is exactly why I hate GRUB2. This is 10x the hack required for GRUB1 to do the same thing. I don't understand why it has to be this complicated. And I fail to see how a bunch of config files spread all over the place and requiring programs to run with them (not just a simple text edit to menu.1st) is an improvement. Also, no longer is all the important config contained within /boot like it SHOULD be.

UUID is a hack in itself and shouldn't be the only easy option.

Thank you MountainX for this excellent summary.