Trouble shooting grub

hari85 · 07-21-2010, 04:10 AM

hai i have a problem with my grub.
my distro is centos 5.3 .
today i boot the computer,i saw an error "grub stage2 is not loaded"
and the system is halted. is it needed to reinstall grub? pls give me the step-by-step solution.
Thanks in Advance............

Filip_Kv · 07-21-2010, 05:13 AM

Did you tamper with the menu.lst (or the grub.conf) file? Stage 2 in GRUB is the part where it loads
the kernels and other OSs to boot from. The file from which it reads these options is menu.lst, or grub.conf in
/boot/grub/. This file might have been corrupted, or otherwise tampered.

However, other errors, such as disk errors, or filesystem errors might be the culprits. Try UBCD in order
to check your system for such errors.

You can also boot with a live cd (ubuntu for instance) and go to the root drive's /boot/grub/ directory and
check the menu.lst file. You have to be careful though, since these files control the boot process of your pc
and mistakes may lead making your pc unbootable.

-Fk

hari85 · 07-21-2010, 11:53 PM

Quote:

Originally Posted by Filip_Kv

Did you tamper with the menu.lst (or the grub.conf) file? Stage 2 in GRUB is the part where it loads
the kernels and other OSs to boot from. The file from which it reads these options is menu.lst, or grub.conf in
/boot/grub/. This file might have been corrupted, or otherwise tampered.

However, other errors, such as disk errors, or filesystem errors might be the culprits. Try UBCD in order
to check your system for such errors.

You can also boot with a live cd (ubuntu for instance) and go to the root drive's /boot/grub/ directory and
check the menu.lst file. You have to be careful though, since these files control the boot process of your pc
and mistakes may lead making your pc unbootable.

-Fk

..................................
thank u very much.. i correct it by some edit in grub.conf.
can u tell me when ever will be single user mode helpful in trouble shooting. i know it is helpful for changing password.
......................................................

hari85 · 07-22-2010, 12:10 AM

Quote:

Originally Posted by Filip_Kv

Did you tamper with the menu.lst (or the grub.conf) file? Stage 2 in GRUB is the part where it loads
the kernels and other OSs to boot from. The file from which it reads these options is menu.lst, or grub.conf in
/boot/grub/. This file might have been corrupted, or otherwise tampered.

However, other errors, such as disk errors, or filesystem errors might be the culprits. Try UBCD in order
to check your system for such errors.

You can also boot with a live cd (ubuntu for instance) and go to the root drive's /boot/grub/ directory and
check the menu.lst file. You have to be careful though, since these files control the boot process of your pc
and mistakes may lead making your pc unbootable.

-Fk

..................................
thank u very much.. i correct it by some edit in grub.conf.
can u tell me when ever will be single user mode helpful in trouble shooting. i know it is helpful for changing password.
......................................................

Filip_Kv · 07-22-2010, 02:22 AM

Single user mode is very helpful for various reasons, one of which is when you forget the root password. It allows you to boot into single user (runlevel 1) and from there change it back to something else. Furthermore, it is also used for securoty purposes, especially when you would like to check something without the network services being run (that happens in single user mode), meaning without any external interference.

Also, concerning the root password change, I would recommend to secure grub with a password to edit its grub menu on startup, since without this it is considered to be a security vulnerability.

-Fk