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Linux31 06-24-2007 03:05 PM

Basic GRUB multiple HD install question
Can anyone tell me how to install linux to a SATA drive and ensure that GRUB is there and will be the boot drive when I also have an IDE drive online (hda)?

I can never get things to boot and I think that the distribution (doesn't matter which, FC, CentOS, Debian, etc.) installs to the SATA but puts GRUB on the hda.

I'd like to have both drives hooked up at installation so that they become part of the same logical volume (or is it group) under LVM.

Thanks for any help you can provide.

saikee 06-24-2007 03:13 PM

Grub can live in any Sata and IDE disk, be it an internal or an external USB disk. Grub can boot from any hard disk in any partition type it supports, like Fat16, Fat32, Ext2/3, Reisefs etc but not ntfs.

However LVM is not recognised by Grub or Lilo or any other boot loader. Ever wonder why Red Hat has to put Grub in its own /boot partition in Ext2/3 while everything is neatly packed inside a LVM?

Thus your problem is over if you forget about putting Grub inside a LVM.

You will have a /boot/grub directory in any Linux, right? Choose any partition Grub supports and copy its directory across. Say if this new directory is the 7th partition of the 4th disk, known to Grub as (hd3,6) as Grub counts from 0, then you can install Grub in the MBR (of the first boot disk (hd0)) by commands in a Grub shell

root (hd3,6)
setup (hd0)

I have installed 5 to 6 Linux over the weekend by booting the iso images directly off the hard disk and had to create Grub in the above manner. So I can guarantee it works.

Linux31 06-24-2007 06:22 PM

Thanks for the feedback. I think I made things unecessarily confused so let me try again.

Anytime I try to install any distribution and have more than one HD in the machine, the subsequent startup after the installation will choke as if it can't find Grub. As soon as I take out one of the drives and re-install with everything on just one drive. No problem. Then later I can add in the second HD.

But that second drive would not be part of the original LVM. Maybe I'm reflecting my Windows experience but without drive letters, etc. how will Linux see and access the second drive if it isn't part of that original LVM volume?

Or am I thinking there's a problem when there isn't?

Thanks again for the help.

Keithj 06-24-2007 06:34 PM

I may be misunderstanding you, but as long as the "basic" Grub boot is on the booting drive, you can have the menu.lst anywhere you like. Each drive (eg hd2,2 - aka hdc3) will have its own Grub folder with the stuff needed by the distro on that drive.

You can decide which drive's Grub folder is to have the menu.lst that actually runs on boot-up. Sometimes, a distro will decide and change it - still not a problem as long as you know where it is.

My machine has 3 HDs, imaginatively called hda hdb and hdc (or in Grub parlance, hd0, hd1, and hd2). Each is partitioned into several more logical drives, with different distros on most of them.

menu.lst is on hdb2, for no other reason than Mepis insisted that's where it should be. When Mepis had a bad hair day last week, I booted from a Grub floppy, with no problems, and started the Fedora installation (on hdc1). From Fedora, I edited the goofed menu.lst on hdb2 and we are back in business.

Does that help?

saikee 06-24-2007 08:06 PM

I don't use LVM as I get nothing out of it.

However I run 5 hard disks in one PC, 2 Sata and 5 Pata built up by adding one disk at a time . Between them I have 150+ partitions and each filled with a bootable systems. Every 120+ Linux has its own boot loader sitting comfortably inside its root partition. It is entirely up to me to select any one to take over the MBR. I can edit any menu.lst (for Grub) to boot all the systems. Lilo can only manage 27 images so I have to use Grub.

Grub identifies the partition number and disk number to boot a Linux. Thereafter the control is passed over to the kernel. Like I said your problem is LVM-related because the same kernel is having a problem to sort out the situation of a changed LVM and trying to adjust everything.

Once the kernel has been loaded in the memory Grub will bugger off and never to be seen again.

Therefore Grub has nothing to do with your problem. It can't even recognise a LVM.

If you ditch the LVM you will experience no problem from Grub. A Linux can be moved from partition to partition and from hard disk to hard disk as long as you don't don't stick in a LVM into it.

Linux31 06-25-2007 07:11 PM

Thanks to everyone for their help. It got me thinking and it looks like the solution to all of my questions was to hook up both HDs during the Linux install and then on re-boot, when things hung, just go back into the MB bios and reverse the boot order of the HDs.

Thanks again to everyone for their help.

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