New grub problem on FC7 - suggestions anyone?

[Mikkel L. Ellertson]

William W. Austin wrote:
> Yesterday I installed a new kernel - kernel-2.6.22.5-76.fc7 (installed 
> via rpm -ivh - I never remove old kernels until I am *sure* that the 
> new one is OK).
> 
> That is the ONLY new package I have installed since the last reboot 
> (about a week ago).  This morning I had to reboot (I wanted to install 
> a new video card), and I did so ... but then remembered something I had 
> to do first, so I just let the reboot cycle continue.
> 
> New problem: grub no longer boots the system.  I tried again after full 
> power-down.  Same result.  Eventually after the usual HW/bios startup 
> messages I get a black screen, and the word GRUB appears.  Then several 
> seconds another GRUB is added.  I let this run while I ran an errand - 
> and it continued that way "GRUB   GRUB    ... etc" for over an hour.  
> There were _no_ error messages.  I was able to reboot using the rescue 
> CD, and did full fsck's of all drives.  Luckily I have another working 
> system here with a burner and I created a boot CD so that I can get the 
> machine to boot.
> 
> After I got the machine to boot using a boot cd, I did a grub-install, 
> but the results are different - I get Error 17 (which is cannot mount 
> selected partition).
> 
> This tells me that the wrong drive is being found by grub - this is a 
> server with 5 large drives on it).  But beyond that I am stumped.
> 
> I've been RTFM'ing, but so far I haven't found any way to get grub to 
> find the right drive in the boot process - or to tell me WHICH drive it
> actually is finding. (And I checked my grub.conf against a backup copy. 
> Except for adding the new kernel, they are identical.)  Removing the 
> new kernel did not help (nor did re-installing it).
> 
> Any suggestions would be welcome - not having grub working is 
> inconvenient at best.
> 
The normal way to fix this is to boot the install CD/DVD and type
rescue at the prompt to boot in the rescue mode. Let it mount the
partitions for you. The chroot to the root file system mount point,
and run grub-install from there. (I can not remember the mount point
right now...)

Dumb question time - do you have a separate /boot partition, or is
it part of your root partition? This sounds like it could be that
grub can not read the grub.conf file. A new one has to be written
when you install the new kernel. But in that case, I would expect
that grub would give you the grub prompt, and wait there. You could
then boot the old kernel if you remember the kernel and initrd lines
for it.

If I remember right, grub-install can also fail if the BIOS drive
mapping is not the same as it will be when the system boots. One way
this can happen is if you are selecting a drive other then the first
one to boot from normally. When you boot from a CD/DVD, most BIOS's
will revert to the default drive mapping, so your normal boot drive
will not be the one the BIOS says is the first drive. I know I have
run into this when doing an install to a USB drive.

Then again, I could be totally off base here - it is late, and my
head is fuzzy. It makes it hard to think. :(
Mikkel
-- 

  Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!

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