Grub issues

[jesse205 at gmail.com]

The partition sda1 had been windows at one point, but I reinstalled windows  
on a sdb (not today). The partition sda3 has always been the ubuntu  
partition (a monolithic system as far as mount points). I guess the issue  
is that today I reformatted sda1 to use as /var/backup and so I wiped out  
that original MBR?

Do I really need to reinstall Ubuntu on sda3? I'm mostly afraid of losing  
the system, I do have a backup but its kinda pieced together and I think it  
could end up being painful for me if I had to reinstall...

I'm pretty familiar with using the installation disc, I know what you mean  
about not letting it format anything. But, what will happen if I reinstall  
over the existing installation?

Isn't there a way to use the live CD just to repair the MBR?

Thanks,



On Mar 18, 2009 6:51pm, Jerry Feldman <gaf at blu.org> wrote:
> I have fixed this on several occasions, mostly by my own tinkering.


> In the past, what I did was to reinstall without formattting.


> One question, is /boot part of your regular root file system (eg.  
> /dev/sda3) or was it originally /dev/sda1. Remember the /boot grub stage2  
> must reside within the first 1024 cylinders. It is normally prudent to  
> keep it in the first physical partition although not required.  
> Essentially the MBR must be able to record the physical address of the  
> grub stage 2. Also note that in a reinstall, you don't need to reinstall  
> and overwrite anything. You just want to force a reinstall of grub. This  
> will also install your kernels in the right place.





> I don't know what your super-grub-disc did, but I've always used the  
> original installation CD/DVD I used to install the system in the first  
> place. The one important thing to remember is that if you do not have a  
> separate /home partition, to make sure you do NOT format the root file  
> system. Also note that the preferred name of menu.lst is now grub.conf,  
> but several distros, such as ubuntu use menu.lst with no grub.conf,  
> others have grub.conf with menu.lst as a symlink.


> Again, let me reiterate, when you go to the manual partition menu, make  
> sure you do not have format checked. It's been a whil since I have used  
> this procedure on my laptop since I've taken the upgrade install path. I  
> forget if ubuntu actually gives you access to the packages you want to  
> install. If so, make sure that grub is to be reinstalled, but you don't  
> have to worry about other stuff. It should not deinstall stuff you  
> already have. You may also be able to fix things directly from your live  
> CD, but the main issue is to be able to rebuild the MBR. You can later  
> add the Windows boot section or let the installer set that up for you.





> On 03/18/2009 12:33 PM, Jesse Lazar wrote:




> Hello,


> I kinda hosed my boot loader, was wondering if anyone could point me in  
> the direction of putting the pieces back together.


> The computer is my desktop pc. I have two drives: the first has four  
> partitions and the second has only one.


> sda1 is 10GB, ext3, unused


> sda2 is 130GB, NTFS, storage of files (shared with windows)


> sda3 is 10GB, ext3, this is where the Ubuntu system lives


> sda4 is 1GB, swap


> sdb is 20GB, this disk has windows on it


> I re-installed grub a couple times as I was not able to boot my Ubuntu  
> system directly, was having to use a "super-grub-disc" (this is after  
> re-mapping the drives in grub so I could boot windows). Whatever I did  
> last I acutally wiped out the grub installation, there is no "menu.1st"  
> or kernel on sda3.













> --


> Jerry Feldman gaf at blu.org>


> Boston Linux and Unix


> PGP key id: 537C5846


> PGP Key fingerprint: 3D1B 8377 A3C0 A5F2 ECBB CA3B 4607 4319 537C 5846









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