On Tue, 2007-09-25 at 10:08 +0930, Michael Kratz wrote:
On 25/09/2007, at 6:41 AM, Scott Silva wrote:
Alfred von Campe spake the following on 9/24/2007 1:59 PM:
Today I decided to install all the latest updates (including the -06 kernel). The "yum update" seems to have run just fine (no errors), but when I rebooted the system it just sits there with the word "GRUB" in the upper left hand corner. I booted from the CentOS 4.5 install CD into rescue mode, did a "chroot /mnt/ sysimage" and reinstalled grub and the latest kernel, but it still gets stuck in the same place. It's not that I can't boot the new kernel; I can't even get to the grub screen!
I have seen this behavior before when the BIOS device order does not match what is seen by the running system. Seems that in such cases, running GRUB from the boot media also sees different device/controller ordering than the running system and can lead to GRUB being confused about where to find the stage1 part of the GRUB code. Either changing the device order in the BIOS settings (if that is an option) or changing the order controllers are found in /etc/modprobe.conf seems to help. In any case, check /boot/grub/device.map and assure that it matches what GRUB sees at boot time. Can check this with the GRUB shell "find" command.
I'll answer my own question. In addition to re-installing grub, a "grub-install /dev/sda" was required to get the system to boot. I thought that reinstalling grub via yum/rpm would take care of it, but apparently it didn't. Lesson learned, panic averted. Alfred
That is what most of us probably thought you meant when you said you re-installed grub.
The reinstall of GRUB seems to have been a noop in this case. Helping the boot-loader part of GRUB find the /boot/grub/stageX files by running grub-install was the fix. What is still open to question is what changed on the system to make GRUB lose its pointer to the /boot/grub directory. Usually takes a change in BIOS settings or actual hardware configuration to change the device order.
Out of interest, is this something that is always required when upgrading Grub?
i.e. should one always manually run "grub-install" /dev/XXX" after doing so?
AFAIK that should not be necessary.
Phil