Swap Partitions (again)

[Wiltse Carpenter]

In article <1990Sep25.132534.16796 at cid.aes.doe.CA> aspgasd at cid.aes.doe.CA (Alain St-Denis) writes:
>Ok, here's the scenario:
>
>I want to have my default swap partition on another drive than the one
>occupied by root. So, I change SWAPDEV in /usr/sysgen/system
>accordingly and I remake /dev/swap and /dev/rswap. I then rebuild the
>kernel. Everything seems fine, the values have been changed in the
>kernel. So I reboot and guess what, it still uses the old default swap
>partition (I want xyl0d1s1 and get xyl0d0s1). Anybody have an idea
>what is wrong here? By the way, this was done on a 4D/240S. I tested
>the same procedure with a 4D/20 (a different partition on the same
>disk) and it worked...

You need to unset the non-volatile ram variable "root" in the prom.  You
can do this by getting into prom manual mode and typing:

	unsetenv root

If root is set, swap automatically gets placed at partition root+1.  On
the 4D/20 and 4D/25, root is not saved in the n.v. ram.  It still works
if you set before you boot though.

>
>Also, since we want to move our swap space and use the whole disk, we
>figured that it would be a good idea to have a miniroot that starts
>from a partition of our choice. So I naively defined the constant
>MINIROOT in /usr/sysgen/system (CCOPTS).

You probably don't want to build a mini-root kernel at all.  In fact,
I'm sure you don't.

The mini-root is used for system software installation and crash recovery.
In both of these cases a complete filesystem is copied from a tape or
remote machine onto the swap partition and booted.  To boot the mini-root
on an alternate disk you would have to manually copy it there and
specify an alternate root on the boot command like this:

	sash>> boot -f dksc(0,5,0)unix.IP6 root=dks0d5s0

>Any idea, anyone (SGI maybe)?

You are treading on what might best be termed ``Advanced Configurations''
here.  Good luck.

	-Wiltse