How to Multi-boot (Maintain more then 2 OS)

[kk0sse54]

Quick question I have ubuntu and xp set up as a dual boot but i want to also create a new partition for Mandriva. If i just install Mandriva the normal way on a separate partition and reinstall GRUB and just manually update the list each time I do a kernel update that should be fine right?

[bodhi.zazen]

Quick question I have ubuntu and xp set up as a dual boot but i want to also create a new partition for Mandriva. If i just install Mandriva the normal way on a separate partition and reinstall GRUB and just manually update the list each time I do a kernel update that should be fine right?

Should work just fine. Worse case secenario you may need to copy the Windows and Ubuntu stanzas from Ubuntu /boot/grub/menu.lst to Mandriva /boot/grub/menu.lst, but I think the Mandriva installer is reasonably reliable and should do this for you. If you elect not to chainload, you will have to manually update the Ubuntu kernel line in Mandirva /boot/grub/menu.lst , if that makse sense ...

[Dedoimedo]

Hi,

Cloud, I would suggest you backup your Ubuntu GRUB, just in case. Whenever you think of modifying the GRUB, installing new distros, changing partition size etc, it's always a good idea to backup.

sudo cp /boot/grub/menu.lst /boot/grub/menu.lst-backup

Cheers,
Dedoimedo

[kk0sse54]

sweet thanks

[kk0sse54]

Another question here for future reference. I know what needs to be done to manually update GRUB and I know how but is there a terminal command that will show me the new kernel I just downloaded and installed so that I will be able to update the GRUB list correctly?

[bodhi.zazen]

ls /boot | grep vmlinuz

[unutbu]

bodhi.zazen, thank you for writing this tutorial!

Would you please take a look at klaasvanschelven's method?

The main difference is that configfile lines in menu.lst take the place of chainloader +1 commands.
This allows you to avoid having to install GRUB on every OS partition.
The menu.lst on the dedicated grub partition hands off to other OS's menu.lst this way:

title        Ubuntu Gusty Gibbon
configfile   (hd0,7)/boot/grub/menu.lst

title        Ubuntu Hardy Heron
configfile   (hd0,8)/boot/grub/menu.lst

His placement of the /home partition to the left of (before) the OS's allows new OS's to be added neatly so you end up with

GRUB partition
home partition
...
OS3 partition
OS2 partition
OS1 partition
swap

Cons to klaasvanschelven's method:
1) Adding a new OS partition will change GRUB's numbering for all the partitions after it. So adding a new OS would mean having to update menu.lst in a number of places. The only way to avoid this (that I see) is to always add new partitions to the right of all other partitions, but that is not going to work for very long since you would have to always to make the right-most partition your largest partition to give it the ability to be shrunk to make room for the next OS. Most people want /home to be big, not the latest OS... So maybe klaasvanschelven's arrangement is as good as it can get.

2) He uses a commonly shared /home partition, I see now from this thread that there can be problems with that. However, this is easily fixed. As you already mentioned, just share a /data partition, not /homes.

[bodhi.zazen]

bodhi.zazen, thank you for writing this tutorial!

Would you please take a look at klaasvanschelven's method?

The main difference is that configfile lines in menu.lst take the place of chainloader +1 commands.
This allows you to avoid having to install GRUB on every OS partition.

<clip>

Thanks for the comments unutbu. I added the information to my tutorial.

My comments are that :

1. Yes, grub must be installed in the target partition. If you look at klaasvanschelven's post grub is installed in the target partition:

after this, mount sda8 and sda6. I then just copied the whole grub directory (from /boot/grub) to sda6. (sudo cp -R /mnt/sda8/boot/grub /mnt/sda6 )

I then replaced the menu section in the menu.lst (on sda6!) by this: ...

In this case klaasvanschelven installed grub by copying the the grub directory and then manually updating it.

2. Your comments re: partition numbering, both with grub (hd0,0) and linux /dev/sda1 are right on target. That is why I listed "things you should already know".

[adrian15]

How to Multi-boot (Maintain more then 2 OS)

Hi bodhi.zazen, you might be interested to update your multiboot howto in the linux part with the Super Grub Disk method:

Multi Distribution Boot Howto

adrian15

[logos34]

Why didn't you include 'symlink' method? It directly boots the most recent kernel via the symbolic link in / or /boot, bypassing menu.lst altogether. No second menu.lst, hence no need to adjust the 'timeout' and 'hiddenmenu' option of each OS. I use it a lot.

Also, to avoid confusion you might want to distinguish between installing Grub in a partition (i.e. the grub folder with kernel images, menu.lst, various stage files, etc.) vs. writing the Grub IPL code to the first/boot sector of the / (or separate /boot) partition:

Your statement in the configfile section:

Caveats :

* grub must be installed in the target partition (hd0,1) and (hd0,1) in the above example.

initially confused me (and perhaps also another poster, unutbu) because I thought you were referring to the chainloader requirements ("in" and "into" the "target" partition):

The "trick" is you need to install GRUB into your (target) root partition.

By far, the easiest way to do this is to install grub BOTH to the MBR and your root (or /boot) partition with each install.

I know you didn't mean to imply that, since the configfile method grabs the menu.lst directly and does not require the Grub IPL to be written to the / or /boot partition -- only the chainloader approach needs it. But it might be clarified by rewording. (On the other hand, it won't hurt to write the grub IPL to every partition)