[Techtalk] still fedup after fedora upgrade

[Wim De Smet]

Hi,


On Sun, Jun 29, 2014 at 9:43 AM, Meryll Larkin <mll at alwanza.com> wrote:

> Haven't found anything in the logs yet that would indicate why it boots
> into
> rescue mode.
> In fact the boot log says:
>   Reached target system initialization
>   Starting Rescue shell
>  Reached Target Rescue Mode
> (that was the last line)
>
> One line right after the other, as if the target system initialization IS
> the rescue shell.  I don't see any errors in the boot.log.
>
> /etc/fstab hasn't changed since January 2013 and it was working fine then,
> but it does have an entry that looks strange to me.
> I KNOW that the boot partition is on /dev/sda1, but in the fstab it doesn't
> look that way:
>
> /dev/mapper/vg_cedar-lv_root /                       ext4    defaults
> 1 1
> UUID=2b4740df-d050-4720-a7cf-b3d6e4ef7faf /boot                   ext4
> defaults        1 2
> /dev/mapper/vg_cedar-lv_home /home                   ext4    defaults
> 1 2
> /dev/mapper/vg_cedar-lv_swap swap                    swap    defaults
> 0 0
> tmpfs                   /dev/shm                tmpfs   defaults        0 0
> devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
> sysfs                   /sys                    sysfs   defaults        0 0
> proc                    /proc                   proc    defaults        0 0
>

That's just the /dev/sda1 entry replaced by a UUID so that if you were to
move the disk and it would end up on /dev/sdb, it would still boot. You can
change it back to /dev/sda1 but I don't think it will change anything,
unless the UUID is wrong of course. Check it by running 'blkid' on
/dev/sda1.


>
> I could mess with the boot entry in fstab and reboot, if it breaks, I can
> use Fedora 20 Live CD to fix it (again, again).
>
> The ArchWiki reminds me that I never ran grub-mkconfig -o
> /boot/grub/grub.cfg
>
> But the ArchWiki confuses me and that scares me because creating a binary
> might not be as easy to revert as changing text configurations.
>
> For example, the ArchWiki indicates I should use these command:
>      # grub-install --target=i386-pc --recheck --debug /dev/sdx
>      # grub-mkconfig -o /boot/grub/grub.cfg
>
> But I don't understand those commands.
> 1. My system is x86_64,  why am I writing "i386"?
> 2.  grub doesn't exist anymore.  Fedora 20 uses grub2
>
> So both of those commands look questionable to me and I don't know if I
> should adapt them, how I should adapt them, or if I should use them
> completely as is (after changing the /dev/sdx  to /dev/sda).
>

Since this is Fedora the correct place to look would be
https://fedoraproject.org/wiki/GRUB_2?rd=Grub2#Updating_GRUB_2_configuration_on_BIOS_systems
no?

In particular, try installing with grub2-install, i.e.
# grub2-install /dev/sda

Things I would try would include reinstalling the kernel, since that'll
cause the install scripts to update the grub2 entries. After running
grub2-install so you're sure the bootloader is installed correctly (stage 1
or whatever they call it these days).

regards,
Wim