My grub2 experience and opinion

[Peter Zoeller]

Going from Fedora 15 with grub to Fedora16 with grub2

I had the pleasure of upgrading my system recently from F15 to F16. The upgrade using PreUpgrade worked beautifully. However what trashed my system was Grub2. In my estimation grub2 is a kludge and it doesn't work properly. Grub was a beautiful step up from Lilo both in simplicity, ease of use and ease of control. Grub2 in my estimation is a regression. It obviously is written by a bunch of Microsoft heads who totally miss the KISS principle. I have gone back to installing and using grub.

So how did it break my system. It doesn't read the drive geometry correctly. It is a step back by assigning hex code to partitions and does so incorrectly. I thought I had seen the last of hex code when I left college in the seventies and had to learn to read core dumps. Now I find I have to relearn it in order to deal with UUID assignments. No wonder Linux doesn't make it into the mainstream.

A boot loader is supposed to boot a system and that is all it should do which grub does marvelously well. System setup and configuration should and must be left to the operating systems and systemd. To display what I mean by grub2 screwing things up let me show you.

Fdisk of my main drive...

address@hidden grayhawk]# fdisk /dev/sda

Command (m for help): p

Disk /dev/sda: 160.0 GB, 160041885696 bytes

255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x000b485f

Device Boot Start End Blocks Id System

/dev/sda1 * 63 144584999 72292468+ 83 Linux

/dev/sda2 144585000 186530714 20972857+ 83 Linux

/dev/sda3 186530715 225616859 19543072+ 83 Linux

/dev/sda4 225616860 312576704 43479922+ 5 Extended

/dev/sda5 225616923 264703004 19543041 83 Linux

/dev/sda6 264703068 303789149 19543041 83 Linux

/dev/sda7 303789213 312576704 4393746 82 Linux swap / Solaris

Df of my partitions as read when they are mounted.....

address@hidden ~]# df -T

Filesystem Type 1K-blocks Used Available Use% Mounted on

rootfs rootfs 71104256 32761604 34728032 49% /

devtmpfs devtmpfs 991944 0 991944 0% /dev

tmpfs tmpfs 1000572 264 1000308 1% /dev/shm

tmpfs tmpfs 1000572 692 999880 1% /run

/dev/sda1 ext3 71104256 32761604 34728032 49% /

tmpfs tmpfs 1000572 0 1000572 0% /sys/fs/cgroup

tmpfs tmpfs 1000572 0 1000572 0% /media

/dev/sda2 ext3 20596820 12864132 6684048 66% /mnt/sda2

/dev/sda3 reiserfs 19542436 14015280 5527156 72% /mnt/sda3

/dev/sda5 reiserfs 19542436 12561496 6980940 65% /mnt/sda5

/dev/sda6 ext3 19191340 4730784 13483404 26% /mnt/sda6

Here is the grub2 configuration file that messed up the system

### BEGIN /etc/grub.d/10_linux ###

menuentry 'Fedora (3.4.6-1.fc16.i686.PAE)' --class fedora --class gnu-linux --class gnu --class os {

load_video

set gfxpayload=keep

insmod gzio

insmod part_msdos

insmod ext2

set root='(hd0,msdos1)'

search --no-floppy --fs-uuid --set=root abc67dd1-53b1-47ca-a27f-0c7d84829f51

echo 'Loading Fedora (3.4.6-1.fc16.i686.PAE)'

linux /boot/vmlinuz-3.4.6-1.fc16.i686.PAE root=UUID=6c3c0e3d-2708-439f-beb7-b9937d1d5f0a ro rd.md=0 rd.lvm=0 rd.dm=0 KEYTABLE=us quiet SYSFONT=latarcyrheb-sun16 rhgb rd.luks=0 LANG=en_US.UTF-8

echo 'Loading initial ramdisk ...'

initrd /boot/initramfs-3.4.6-1.fc16.i686.PAE.img

}

menuentry 'Fedora Linux, with Linux 3.4.4-4.fc16.i686.PAE' --class fedora --class gnu-linux --class gnu --class os {

load_video

set gfxpayload=keep

insmod gzio

insmod part_msdos

insmod ext2

set root='(hd0,msdos1)'

search --no-floppy --fs-uuid --set=root abc67dd1-53b1-47ca-a27f-0c7d84829f51

echo 'Loading Linux 3.4.4-4.fc16.i686.PAE ...'

linux /boot/vmlinuz-3.4.4-4.fc16.i686.PAE root=UUID=abc67dd1-53b1-47ca-a27f-0c7d84829f51 ro rd.md=0 rd.lvm=0 rd.dm=0 KEYTABLE=us quiet SYSFONT=latarcyrheb-sun16 rhgb rd.luks=0 LANG=en_US.UTF-8

echo 'Loading initial ramdisk ...'

initrd /boot/initramfs-3.4.4-4.fc16.i686.PAE.img

}

menuentry 'Fedora Linux, with Linux 3.4.4-4.fc16.i686.PAE (recovery mode)' --class fedora --class gnu-linux --class gnu --class os {

load_video

set gfxpayload=keep

insmod gzio

insmod part_msdos

insmod ext2

set root='(hd0,msdos1)'

search --no-floppy --fs-uuid --set=root abc67dd1-53b1-47ca-a27f-0c7d84829f51

echo 'Loading Linux 3.4.4-4.fc16.i686.PAE ...'

linux /boot/vmlinuz-3.4.4-4.fc16.i686.PAE root=UUID=abc67dd1-53b1-47ca-a27f-0c7d84829f51 ro single rd.md=0 rd.lvm=0 rd.dm=0 KEYTABLE=us quiet SYSFONT=latarcyrheb-sun16 rhgb rd.luks=0 LANG=en_US.UTF-8

echo 'Loading initial ramdisk ...'

initrd /boot/initramfs-3.4.4-4.fc16.i686.PAE.img

}

### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###

### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/30_os-prober ###

menuentry "Fedora (2.6.38.6-26.rc1.fc15.i686.PAE) (on /dev/sda2)" --class gnu-linux --class gnu --class os {

insmod part_msdos

insmod ext2

set root='(hd0,msdos2)'

search --no-floppy --fs-uuid --set=root 6c3c0e3d-2708-439f-beb7-b9937d1d5f0a

linux /boot/vmlinuz-2.6.38.6-26.rc1.fc15.i686.PAE ro root=/dev/sda1 KEYTABLE=us rhgb quiet

initrd /boot/initramfs-2.6.38.6-26.rc1.fc15.i686.PAE.img

}

menuentry "Fedora (2.6.38.6-26.rc1.fc15.i686.PAE) (on /dev/sda2)" --class gnu-linux --class gnu --class os {

insmod part_msdos

insmod ext2

set root='(hd0,msdos2)'

search --no-floppy --fs-uuid --set=root 6c3c0e3d-2708-439f-beb7-b9937d1d5f0a

linux /boot/vmlinuz-2.6.38.6-26.rc1.fc15.i686.PAE ro root=/dev/sda2 KEYTABLE=us rhgb quiet

initrd /boot/initramfs-2.6.38.6-26.rc1.fc15.i686.PAE.img

}

menuentry "KNOPPIX (on /dev/sda3)" --class gnu-linux --class gnu --class os {

insmod part_msdos

insmod reiserfs

set root='(hd0,msdos3)'

search --no-floppy --fs-uuid --set=root 8cd61602-4981-4b11-a2f8-8e06bd4baff2

linux /boot/vmlinuz root=/dev/sda1 rootwait lang=us apm=power-off nomce libata.force=noncq tz=localtime loglevel=1 rw

}

menuentry "Debian GNU/Linux, kernel 2.6.37-64 Default (on /dev/sda3)" --class gnu-linux --class gnu --class os {

insmod part_msdos

insmod reiserfs

set root='(hd0,msdos3)'

search --no-floppy --fs-uuid --set=root 8cd61602-4981-4b11-a2f8-8e06bd4baff2

linux /boot/vmlinuz-2.6.37-64 root=/dev/sda1 ro lang=us apm=power-off tz=localtime vga=791

}

menuentry "KNOPPIX (on /dev/sda5)" --class gnu-linux --class gnu --class os {

insmod part_msdos

insmod reiserfs

set root='(hd0,msdos5)'

search --no-floppy --fs-uuid --set=root 89b7ce78-6ccf-4fc4-9af2-2a392494473b

linux /boot/vmlinuz root=/dev/sda5 rootwait lang=us apm=power-off vga=791 nomce loglevel=0 quiet rw

}

menuentry "Fedora (2.6.38.6-26.rc1.fc15.i686.PAE) (on /dev/sda6)" --class gnu-linux --class gnu --class os {

insmod part_msdos

insmod ext2

set root='(hd0,msdos6)'

search --no-floppy --fs-uuid --set=root 44c1d6b1-51f2-4eac-880f-9262996556d6

linux /boot/vmlinuz-2.6.38.6-26.rc1.fc15.i686.PAE ro root=UUID=44c1d6b1-51f2-4eac-880f-9262996556d6 rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYTABLE=us rhgb quiet

initrd /boot/initramfs-2.6.38.6-26.rc1.fc15.i686.PAE.img

}

So what are the issues with this....

I have two fedora partitions sda1 and sda2. It no longer boots the second installation which is a different version of Fedora. I teach Linux and use other installations to learn differences between distros in order to bring this knowledge to class. The second Fedora is not my live system but the same as what was being used in the class.

The third partition sda3 is a reiser file system and a Knoppix hard drive install installed and modified as a Debian distribution. Under grub2 it no longer boots because the kernel can't find the file system. Why grub2 is telling it to look in the wrong place.

The fifth partition sda5 is a pure Knoppix hard drive install and funny enough it does boot.

The remaining one sda6 is at the moment a bad install and should not be part of the boot menu. It is used to install and test out and learn other distros. With grub it was child's play to install other distros make a mod to the grub.conf to include or exclude the new distro. You no longer had to rerun like you did with Lilo and now with grub2 your are back to Lilo times where you must rerun grub2 to have the new configuration installed. Talk about taking a step back.

With Lilo and grub it was easy from the boot loader screen to directly boot into a kernel shell to rescue a pooched hard drive. Like to see how you can do that using grub2?

I have reverted back to using grub, a system that is elegant, simple, well designed and dumped the kludge that grub2 is. I shall continue to use grub and our file server at work that I maintain shall also continue to use grub. I will warn my students about the failures of grub2 and let them decide whether to upgrade to grub2 or stick with grub.