Environment: RHEL 5.2 and 5.4 AP x86_64, 2 drives (sda, sdb), installing without optional features like clustering and virtualization.

Hi,

I have tried this for a couple of days now and just can't get it to work. My goal is to take the RHEL 5.2 DVD and RHEL 5.4 DVD and install them on separate drives of the same machine. I want the grub menu to give me a choice. I prefer to understand the steps and choices offered me by the install dialog to do this rather than fiddle with grub.conf. If that is not possible, I will write up the bug.

So far, I just get the the error 13 when trying to start the grub added second OS. I have read elsewhere that "Anaconda frequently recognizes the other operating system and sets up grub so you can boot from either operating system". That would be nice.

The install dialog lets me choose a drive to install to. I have figured out that I need to check "review and modify partitioning layout" to enter the advanced grub choices. Do I have it install a boot loader for the 1st OS? Trying to add the 1st OS during the second OS install creates a grub conf with no kernel line in the added boot stanza.

If someone could suggest the way to use the install dialog to achieve this, that would be great.

thanks very much,
tongar

It's pretty easy to do. Install one on sda like you normally would. Install the second on drive sdb but in the advanced options for grub configuration just have grub install to your root partition on sdb, eg /dev/sdb1, instead of the mbr. Then go boot up to your RH installation on sda and edit your grub.conf file there to add and entry for the sdb installation. The format is pretty straightforward. If your root partition on sdb is sdb1, it would look like:

title RH-SDB
root (hd1,0)
configfile /boot/grub/grub.conf

Reboot and select RH-SDB. That will chain load the grub on sdb1 so sdb's boot selection screen will pop up. Hit Enter and you will boot into your sdb RH installation.

kilgoretrout,

thanks very much,

Thanks to your post, I'm understanding this better now and I am getting closer, but still have a problem.

I install RH 5.2 on sda using the defaults. This creates a MBR on sda that the machine boots with when restarted.

I then installed RH 5.4 on sdb. Selected to have the boot loader installed on /dev/sdb1, instead of the MBR on sda. The install requires a reboot before you have finished configuration.

On reboot, I am on RH 5.2 on sda. I edit the grub.conf to have:
title RH-SDB
root (hd1,0)
configfile /boot/grub/grub.conf

Then, reboot. Boots to sda, I select RH-SDB and I get the error 15, File not found. The error is right after the line: configfile /boot/grub/grub.conf. Perhaps that is the file it is not finding?

Would this be caused because I have not completed the first boot configuration on the RH 5.4 install? That install was only half done before I had to reboot.

thanks very much for any ideas,
tongar

I got it to work by instead of using the configfile command, copying the title line and associated following commands from the sdb grub.conf to the grub.conf on sda that boots from the MBR. Perhaps adding a prefix, (hd1,0) or (hd1), to the file name on the configfile would have worked but I did not try that.

Doing a "mount" command I saw that the other systems grub.conf was mounted under /media/_boot, so I could get the correct commands.

When I finally did boot the the sdb system, it continued with it's first boot configuration as expected.

I use this server remotely and see that I can choose which OS it boots by changing the default=0 to 0 or 1, which relates to the menu list order. When on sda the grub.conf to edit is in /boot/grub/, when on sdb, it is /media/_boot/grub/ Then "shutdown -r now"

thanks for your help,
tongar

sorry see below

I know this has been inactive for a while, but would like to say a big thanks to kiloretrout for his help on this case which was exactly my case. I read a lot of other solutions, and when I say a lot, I mean all of them, on how to do this. He explained it simple and to the point. I recommend a trophy be given to you. But seriously, thank you, I had this problem for about two weeks.


Cheers