[CentOS] grub problems

Wed Nov 4 07:03:39 UTC 2009
Devin Reade <gdr at gno.org>

m.roth at 5-cent.us <m.roth at 5-cent.us> wrote:

> This is irritating: I've got a server I just upgraded to 5.4, then
> rebooted, only to discover that it just *sits* there at the grub boot
> menu. I looked at grub.conf, and uncommented hiddenmenu (which should have
> been done long ago).

I just saw something similar happen on a server when I was upgrading
it to kernel 2.6.18-164.2.1.el5xen.  In this case, however, it didn't
get to the grub prompt but rather only got as far as printing "GRUB"
and nothing else.  This was on a machine that was originally CentOS 5.3
and was previously upgraded to 5.4.

In this case, I had mirrored OS disks so I was able get into the BIOS, 
and boot from the second disk (which had been previously been set up
with a redundant boot block).  I then reinitialized the boot block on
the first disk (and is the default boot device).

If I didn't have mirrored disks, I would have booted the DVD in rescue mode.

Both the initial grub setup and the reinit were done according to the
info available at <http://grub.enbug.org/MirroringRAID>.

Hopefully that helps.

Devin
-- 
UNIX is very simple, but it takes a genius to understand the simplicity.
							- Dennis Ritchie