[CentOS] Re: Stuck at GRUB

Thu Nov 29 14:24:44 UTC 2007
Ugo Bellavance <ugob at lubik.ca>

jancio_wodnik at wp.pl wrote:
> Christopher Chan pisze:
>>>>>> grub cannot find its second stage. Are you booting from a mirrored 
>>>>>> partition?
>>>>> Yes
>>>> What could be a solution?  And what could have happen upon the reboot?
>>> That is weird.  I just re-installed centos5 and it is now booting 
>>> properly.  What could I do to avoid this situation in the future?
>> IIRC, RHEL4 does not properly handle installation of grub on mirrored 
>> partitions and therefore Centos4 suffers from the same problem.
>> RHEL5 does it properly now as you can see. This has been a long 
>> outstanding problem of anaconda.
> Yeap, this is true. After installing centos4 on RAID1 disk (software 
> raid) i always do:
> grub
> grub>device (hd0) /dev/hdc
> grub>root (hd0,0)       grub>setup (hd0)
> where /dev/hdc is second RAID DISK (it could be whatever: /dev/sdb1 etc)
> So system is booting form first or second riad1 disk

Ok, so to sum up from what I understand of my problem:

Installation of CentOS4 -> Installs grub only on one HDD partition out 
of 2, in the mirror.

One disk fails, the one that has grub

System won't boot because it can't find grub on the other drive.

If I had centos5 there in the first place, the setup would have taken 
care of installing grub on the 2 mirrored raid partitions.

Am I right?

Is there a way to know where grub is installed?  I have a few servers 
running in RAID 1 software for /boot, I gotta fix this.  If I can't tell 
whether it is installed or not, is it dangerous to re-install it using 
the command above?