Op 21/05/2008 om 01:10:05 +0300, schreef Imre Oolberg :
> Some time ago i did experiment with dual-booting (actually
> multi-booting) from one harddisk several OpenBSD instances, for the sake
> of fun. I settled to using dualboot OpenBSD to make upgrades more
> suitable for me (just unpacking new distribution's file sets under /mnt
> mounted empty partition and rebooting).
Right, that's what I am aiming at.
> But as i see it there is to ways of having multiple root i.e. a
> partitions on one physical harddisk
>
> 1. Use only one fdisk partition and in it one OpenBSD root is normal a
> partition and another is in the same disklabel, say g. And so for
> example in this disklabel a, d, e, f partitions belong to one instance
> and g is another (consisting of one filesystem). Two instances share
> only swap partition.
>
> To select between them you need to say at boot> prompt
>
> boot> boot hd0a:/bsd
>
> or
>
> boot> boot hd0g:/bsd
>
> 2. Use severaly fdisk partitions, each has its own disklabel and this
> disklabel is dedicated to one OpenBSD instance. OpenBSD bootloader is on
>
> To select between instances you need to use grub bootloader from binary
> packages
>
> # pkg_add grub
Ah, good OLD grub to the rescue. Thanks, I was staring at openbsd's
boot, but it doesn't seem to have the configurability that e.g. grub
has.
> It goes like this that grub's first stage is in the harddisk's MBR and
> openbsd bootloader's first stage is installed into each fdisk partition,
> i.e. you use chainloading.
>
> See also
>
> /usr/local/share/doc/grub/README.OpenBSD
> /usr/local/share/examples/grub/menu.lst
>
> Essential is to understand that OpenBSD uses first fdisk's OpenBSD A6
> disklabel it sees. Thats why grub fiddles with them.
I am now totally confused about openbsd disk device naming schema.
As I now see it /dev/wd0a refers tho the first ide disk with id 6B
(OpenBSD), label a. As it is the one elected by boot to be the rootfs.
It would make more sense to me to have en naming schema, which refers to
wd$idedisk$partition$label
Now, how can I mount, let's say, the fourth partition, on which I only
want menu.lst to reside on. this can bee a tiny filesystem, with no OS.
So I can
mkfs /dev/$whatever
mount /dev/$whatever /grub
cp /usr/local/share/examples/grub/menu.lst /grub
and move on.
> Leo Baltus wrote:
> >I would like to have more than one openbsd root filesystem on my
> >hardrive. Could somebody please explain how to go about this?
> >
> >In a linux environment I could set up 2 lv's and point to each of them
> >by kernel commandlines.
> >
> >Using openbsd I could use multiple bios-partitions each having an a: label
> >but how do I tel the bootloader to use a specific partition?
> >
> >Maybe there is a way I didn't think of, please let me know.
> >
--
Leo Baltus
