GRUB multiboot with redhat ES and DL380

[Bill McNAMARA_1]

Hi,

I have DL380s G4 and G5's with multiple Raid 0 disks.

Each disk has a seperate OS installed (all redhat).

I want to configure GRUB to offer a choice of which disk to boot from on startup if possible..

or would this be done via the bios.

Are there any considerations with OS installation that I have to take into account..

for example... The plan is to have all disks inserted.. redhat/bios settings will probably call disk in slot 0 hda, slot 1 hdb etc.. will this create impact for reinstalling linux on hdb later on?
Where should grub reside?
What should be configured at the CCISS part...

At the moment, to boot from each disk, I remove all others and am left with a single hda.

Thanks,
Bill

[Stuart Browne]

Hrm.

Interesting problem.

If the goal is to leave all disks in, in a fixed order, then it's definately doable.

If the order changes, or more precisely the first-disk changes, then it makes life very difficult.

You can easily set grub up to boot from the different devices from the same grub config file.

What's probably best is to do the following two things:

In each individual OS, install Grub into the first partition (as against the boot-sector).

This will allow you to have individual (and per-os changes) to the kernel's for updates, if you want that. If not, then skip this bit.

Next is to have the first disks (hopefully the permenant disk) Grub point to each separate disk's first-partition, and 'chainloader' them.

i.e.

title 2nd disk
hd(1,0)
chainloader +1

title 3rd disk
hd(2,0)
chainloader +1

The chain-loader will then ask the device listed (hd(x,0)) for a boot-loader.

It's basically how you multi-boot windows/linux with Grub being the master.

It *WILL* get messy..

Anybody else got a better way? ;)

[Bill McNAMARA_1]

I'm wondering if the map option will help......

for example the windows xp version below changes drive number :

#boot=/dev/hda
default=1
timeout=7
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux AS (2.4.21-20.EL)
root (hd0,0)
kernel /vmlinuz-2.4.21-20.EL ro root=LABEL=/
initrd /initrd-2.4.21-20.EL.img
title Windows XP
root (hd1,0)
map (hd1) (hd0)
map (hd0) (hd1)
makeactive
chainloader +1

[Ivan Ferreira]

I think that is not that simple, I had problems in the past with this because normally, nowdays, grub and fstab uses devices LABELS to mount the file systems.

As the different Linux installations wil all have the same label, then you will always mount the first file system with the matchel label.

It's a very extrange configuration, with virtualization technologies, you souldn't need booting from different disks. Just start another os instance as a guest.

[Steven E. Protter]

Shalom,

Here is how I did it for what its worth.

I had a Windows system on disk 1, nothing on Disk 2.

I installed Linux on disk 2 and let grub be the boot manager for the entire system.

I acheived results that I believe are similar to what you want.

Doing the windows first is the key so it doesn't stomp on grub later.

The grub records will end up on the primary boot disk.

SEP

[Bill McNAMARA_1]

Hi Steven,

Try installing linux on a third disk with GRUB now...

and then on a fourth!

Its easy enough with different OS's but I haven't managed GRUBbing with the same OS. (linux)

Thanks..
Bill

[Bill McNAMARA_1]

any new ideas here? internet searches are not even helping...

I've tried the following, but just can't have more that one redhat install per server.
I want to have 4 raid 0 redhat installs each selectable via grub.

Currently the only way i have is to remove all disks and to install seperately. when I want to boot a different redhat disk, it's a case of travel 100 miles to change a disk...

Bill

[Arnd Kohlen]

Hm, another suggestion is to put grub to a place which doesn't change if you remove or change any of the hard discs: on a floppy disc or usb stick, cd... Even if the saved configuration doesn't work anymore, you can edit the options at boot time (with the "e"-key) to get one of your remaining harddiscs started.

Later you can use udev to identify your harddiscs or partitions to mount them to the appropriate directories so you don't depend on "sda" or "sdb".

But maybe I'm blind and I can't see the real problem ;-)

Regards
Arnd

[Steven E. Protter]

Shalom,

>>
Try installing linux on a third disk with GRUB now...

and then on a fourth!

Its easy enough with different OS's but I haven't managed GRUBbing with the same OS. (linux)
<<

There is a stage in the GUI installation where you can tell the installation what disk to install the MBR/PBR and grub. It should pick up the previous configuration and afterwards present boot options for multiple Linuxes.

I don't have any systems here with three eligible boot disks to just try it out for you.

If the OS can't do it, then I'd go for the CISS/BIOS route, but I think the OS should be able to do this, unless its stepping on itself.

SEP

[Bill McNAMARA_1]

ok, I think I haven't been clear.

I have 4 disks of raid 0 in a proliant dl380.

+-----+-----+-----+-----+
| | | | |
| | | | |
| | | | |
+-----+-----+-----+-----+

when I install one redhat I get this:
+-----+-----+-----+-----+
| | | |rhel3|
| | | |c0d0 |
| | | | |
+-----+-----+-----+-----+

I can reboot the os no problem, grub is the boot loader.

I try to install another disk:
+-----+-----+-----+-----+
| | |rhel3|rhel3|
| | |c0d1 |c0d0 |
| | | | |
+-----+-----+-----+-----+

I cannot now boot from c0d1.

The only os that is available to boot from is d0.

I want to be able to have grub
on all disks proposing a choice of booting
from any disk c0d0 c0d1, c0d2, c0d3

Bill