F8/F9 Multiboot question

[Tim]

On Sat, 2008-08-02 at 20:08 -0700, Daniel B. Thurman wrote:
> What I'd like to know is, how can I convert my existing setup or
> partition layout so that each of the Fedora partitions are bootable
> with grub installed for which chain-loader will work?

When installing extra OSs, don't install the bootloader to the disc MBR,
but to the boot partition for that OS (with each OS having its own boot
partition).

At a simplistic level, you might install an OS with individual
partitions like the following:

system boot  (e.g. /dev/sda1)
Fedora boot  (e.g. /dev/sda2)
Fedora /
Ubuntu boot
Ubuntu /
Debian boot
Debian /
OpenBSD boot
OpenBSD /

The system boot would just be where GRUB has a few files, that the BIOS
will read to start booting.  This will be your boot menu, and to boot
other OSs you'll chainload to their own boot partitions.  When you boot
up, you'll see the initial boot menu (offering just Fedora, Ubuntu,
Debian, OpenBSD, etc., and when you pick one of them, you'll move over
to the boot menu for that distro - where you can pick which particular
kernel they'll boot with, or just go with their defaults).

To change existing installations over to working this way, you'd need to
already have boot partitions for each one, and you'd reinstall their
bootloaders to their own boot partitions.  e.g. You'd install Fedora's
GRUB to /dev/sda2 not /dev/sda.

Some people will share a boot partition between different OSs, but that
*may* be a problem, if one of them updates kernels and messed with
others.  It shouldn't happen, but I've read postings about it.

> In the past, I had nightmares trying to figure this out, and was not
> successful, but then I was not using chain-loaders either. From my
> past experiences, for some reason I got the idea that it was a no-no
> to have /boot installed in / - I forget why exactly - but I found that
> /boot worked if it had it's own partition which explains my particular
> partition layout.  It would save me a partition for other uses if I
> can get /boot embedded within / - that would be very cool!

If boot is just a directory inside /, it might be located on a part of
the disc that the basic motherboard BIOS cannot access, so you won't be
able to boot up.  When you make boot partitions, you can control where
they're created, and create them in a place that BIOS can actually read.

Some people think that a boot directory inside / is fine, rather than a
partition, because it works for them, at *that* time.  But later on, as
they install updates and other files, the location of boot-up files
(e.g. kernel and initrd files) moves around, and can end up in an
unreadable (by the BIOS) place.

-- 
[tim at localhost ~]$ uname -r
2.6.25.11-97.fc9.i686

Don't send private replies to my address, the mailbox is ignored.  I
read messages from the public lists.