Multiple distros, location of the /boot partition and kernel updates

Jongi · #1 3rd August 2006, 09:15 AM

I currently have FC5 as my main OS and have also installed Kubuntu and SUSE10.1. Grub uses the FC5 /boot and menu.lst.

1 - I assume that if I upgrade the Kubuntu kernel I will have to manually update the menu.lst under the FC5 install to reflect the new Ubuntu kernel?

2 - How do I create a new /boot partition and yet not mess up the booting of FC5 and Ubuntu? By create I don't mean the actual creation of a partition, but moving /boot from being on the / partition to its own /boot partition. Not sure that makes sense.

3 - Will creating a separate /boot partition actually solve the problem of having to manually update menu.lst? That is, will menu.lst now reside on the newly created /boot partition and as such available to all the distros?

Jongi · #2 5th August 2006, 03:36 PM

Here's what someone on another forum suggested. Is it likely to work?

Quote:

If you want to really fix this problem, what I typically do is only create a /boot partition for the first linux distro and install that grub to the MBR. Then for all the other distros, I just install grub & /boot to the / partition. Then use the first grub to chainload the second one.

For example, in your case, you would use FC's grub to chainload Kubuntu's grub. Then if you update FC's kernel, it will update the Kubuntu grub menu.lst. But FC's grub doesn't care because it's going to load Kubuntu's grub.

Your partitions might look like this

Code:

/dev/hda1  /boot  -- FC's boot
/dev/hda2  /swap
/dev/hda3  /  -- FC5
/dev/hda5  /  -- Kubuntu
/dev/hda6  /  -- SUSE

A typical grub entry (for your FC grub menu.lst) looks like

Code:

title     Kubuntu
root     (hd0,5)
chainloader +1

Jongi · #3 7th August 2006, 02:25 PM

How would I go about copying my existing grub configuartion on a usb stick so that If i mess up something i can use it to boot the FC5 install?

Jongi · #4 17th October 2006, 01:05 PM

Eventually gonna try this. So need a thumbs up from someone before I do.

riddlermarc · #5 17th October 2006, 02:59 PM

If it all goes pear-shaped and you just want to get back to your Fedora install, you can boot to the Fedora cd/dvd and repair grub from there. Check out the following link for some details:

http://linuxhelp.blogspot.com/2005/1...-and-boot.html

JN4OldSchool · #6 17th October 2006, 03:09 PM

I dont believe this is going to work like you want. If the Ubuntu /boot is in the Ubuntu / partition then why would the FC /boot partition be updated with an Ubuntu kernel change? I havent found a way around this. On dual/multi boot systems I just always put EVERYTHING (including a /home) for each distro in that distro's / partition. Of course they all share a common swap space. Then I create a /share partition for a common shared /home. This way Ubuntus settings wont conflict with FC's settings in /home. I use whatever GRUB is the most convienient, I happen to like the MEPIS grub when I use MEPIS, it really doesnt matter. When you update a non-grub distro just reboot your computer to a live Linux CD (again, I like MEPIS) log in as root and go to the updated distros menu.lst. Just copy the new title entry and open the grub distro's menu.lst and paste it in. Then manually remove the third and oldest kernel entry as you will only want 2 kernel choices. Then just reboot normally. It really isnt much added work and I havent found a better way. Maybe someone else has?

Jongi · #7 17th October 2006, 03:35 PM

JN4: That is what I currently do, except I just copy the menu.lst for the distro i have just updated to the shared partition and update the "main" grub when I boot of FC5.

If you look at the 2nd post, the /boot for subsequent installs would be within the partition of that distro rather than in the seperate /boot partition. FC5's /boot would be in the seperate /boot partition. You would then need to install a grub in the partition of each subsequent OS install.

So on startup the FC5 grub would come up. I choose Kubuntu then that grub comes up. This way all changes that Kubuntu makes to it's menu.lst should come up.

Of course I would have to enter a manual entry in the FC menu.lst to point it to the partition of other distros.

JN4OldSchool · #8 17th October 2006, 04:00 PM

But what have you gained? Doing it my way each seperate distro still has a grub menu.lst that DOES get automatically updated with each kernel change of that distro.

Jongi · #9 18th October 2006, 08:18 AM

I think we are almost saying the same thing. You are saying there is no need for a sepereate /boot partition. Let each distro have it's /boot within it's / partition. But just ensure that the grub of the non main distro (ie all others except for FC) are on the boot partition of that partition instead of being on the MBR.

Have I got that correct?

JN4OldSchool · #10 18th October 2006, 01:31 PM

you dont even install the grubs in any but the main OS. The menu.lst on the...slave distros will still update with kernel changes. If your distro uses lilo you can still use the chainloader +1 to put the title in the main grub.

Jongi · #11 18th October 2006, 03:34 PM

Ah you see the way I want to do it i do not have to copy an extract from say the Kubuntu menu.lst to the FC5 menu.lst. I want the FC5 grub to point to the Kubuntu partition and then the grub for Kubuntu to load and have all the relevant choices (with updated kernels and the like)

JN4OldSchool · #12 18th October 2006, 04:38 PM

ahh ok, I get it now. So you only have to manually configure the main grub once just to point to the slave grubs. Interesting. Let me know if it works.

#13 19th October 2006, 03:57 AM

I have this exact same problem. I have Fedora Core on one hard drive (hda) and Ubuntu on a second (hdb). When I installed Ubuntu, I installed it on hdb, but it installed (overwrote) grub on hda. First boot-up, and it boots directly into Ubuntu. My grub no longer gave me the option to boot into Fedora anymore.

So in Ubuntu, I modified /boot/grub/menu.lst to include the entries required to have Fedora Core as an option when I boot up. I didn't know them off the top of my head, so I had to mount my hda drive from Ubuntu (hdb) in order to copy over the entries.

Problem is, every time I upgrade the Kernel in Ubuntu, the grub config file gets completely messed up, and the entries for Fedora Core get overwritten.

I haven't found a solution for this yet, although I haven't really searched so far (I've just installed Ubuntu a few days ago). So far I have to manually update the grub config files whenever I update the kernel in Fedora or Ubuntu.

Jongi · #14 19th October 2006, 08:55 AM

So if we use the example partitions above, in Kubuntu would I just run grub-install /dev/hda5 to install it's grub. And would putting what is in post #2 in the FC5 grub point it to the Kubuntu grub?