how to get grub2 to work properly in mbr of multi-boot system with lvm
 

Hello forum,
I’m new member, glad to be here and sending greetings to all helping hands out there.

Now here is my story:
After a major breakdown I’m trying to set up a multi boot system like so:

• inevitable XP
• Linux Mint for daily use "out of the box"
• Bodhi for fiddling and fun
• Scientific Linux with focus on security, for coding Salome simulations and other work stuff

This time I decided to use lvm for obvious reasons, I never did this before.

Mint installation went well (including dualboot), but after installing Bodhi I was surprised when the bootmenue only showed Bodhi and XP entries — Mint was gone.

Since then I’m trying to get grub to list all three OSes, but all the infos i could find do not apply, because they either do not cover lvm or multiboot, just dualboot with lvm, what I already have achieved twice ;-)

Here’s some infos that might be of relevance:

• I did not use /boot partitions but wrote grub directly on “sda”
• Filesystem of all Linux partitions is ext4

So now Scientific Linux is yet to be installed, and I hope you people could point me out the proper proceedings so that in the end I can choose among all of them.

Many thanks :wave:

I'f Mint is for daily use, I'll assume it controls grub and its configuration files. Remember only one OS has 'control' of GRUB's menu.

To return control to Mint, do this:
1. From the GRUB menu, press c for GRUB's command line
2. Set root with set root='(hdx,y)' where x is the drive and y the partition on the drive where you installed Mint. Remember partitions start with 1.
3. Load the kernel with linux /boot/vmlinuz....... root=/dev/<lvm root device>. If you don't know the version of the kernel, press <tab> for a list.
4. Load the initramfs with initrd /boot/initrd...... If you don't know the version of the kernel, press <tab> for a list. This must match the kernel.
5. Boot the kernel with the command 'boot'.

Once Mint is loaded give Mint control of GRUB again with:
Update GRUB's menu with:
If you cannot determine the root device or kernel version, you may also do this:
Mount your Mint partition in Bodhi
where sdx is the partition with Mint

Look at your grub.cfg file in Mint:
Look for the first menuentry line. Within the menuentry section, note the set root=, linux and initrd lines. Use these as the values for the Steps 1 to 5 above.

I don't use lvm, do I'm not sure of any specifics for lvm.

If this don't work, post back with any error message.

Thanks towheedm but before I tried your approach I rebooted once again and updated grub and it worked! I have no idea why it didn´t before, I must have messed sth up.

Then I tried to install Scientific Linux, but it does not support grub2. That means you have to have a /boot partition outside the lvm. I didn´t want that so I swiched to CAElinux wich comes with Salome in a package. This one´s a ubuntu derivate so no probs here with grub2.

For now everything is fine :wave: