physical scsi channel mapping to scsiX device node mapping, how to configure manually
 

I have and ncr scsi card and and aic78xx scsi card.
They each have drives attached to them.

when I installed the system looked like this:

scsi0 : ncr53c8xx-3.4.3b-20010512
scsi1 : Adaptec AIC7XXX Rev 6.2.8
scsi2 : Adaptec AIC7XXX Rev 6.2.8
sda
sdb

(no drives attached to ncr53x8xx)

so now I have added some drives to the config and it looks like this:

scsi0 : ncr53c8xx-3.4.3b-20010512
sda
sdb
scsi1 : Adaptec AIC7XXX Rev 6.2.8
scsi2 : Adaptec AIC7XXX Rev 6.2.8
sdc
sdd

and of course it won't boot cause the kernel thinks it's on /dev/sda.

My questions:

what's the most painless way of fixing this problem?

Why am I having so much trouble telling the kernel to make the adaptec card be scsi0 and scsi1 and the ncr card to be scsi2?

I have tried altering my modules.conf in several different ways:

there's the classic but elegant:

alias scsi_hostadapter aic7xxx

and no other scsi dirrectives..

then I tried the full-on:

alias scsi_hostadapter0 aic7xxx
alias scsi_hostadapter1 ncr53x8xx

tangents have included:

alias scsi0 aic7xxx
alias scsi1 aic7xxx
alias scsi2 ncr53x8xx

and

alias ncr53x8xx off

As an aside I have to admit that I am having trouble finding any examples of how to tell the kernel to do what you want it to do in this respect.

Nice one...


are u updated the initrd after changing the modules.conf ??

Open the initrd image and check the sequence.


I think it will solve ur issue..





:study:

Siddiqu.T

initrd is an image of a ram disk with the drivers required to boot, I know that.

However, I did not know that the initrd dictated how to use the drivers and I don't know how it does that (is there a modules.conf in it?).

How do I "Open the initrd image and check the sequence." ?

This just in...

I figured out how to fix my problem

there is a file in the initrd called linuxrc that dictates which drivers should be loaded ( and in what order). It's just a shell script.
I moved the modprobe for the aic card above the modprobe dor the ncr card and voila, I get sda1 to be the drive on the AIC controller. Which is exactly what I wanted.

The tricky part was getting inside the initrd.

I "reverse engineered the creation of the initrd by examining /sbin/mkinitrd which is just a sheel script that automates the creation of an initrd.
So i had to unzip the file and mount it via loopback dev but once I had /sbin/mkinitrd in front of me it was just a step by step process.

If anyone care I can write it out.