Re: Can I define SCSI device order?

[Scott Taylor <scott@dctchambers.com>]

At 04:52 AM 3/10/03, Paul Furness wrote:
>Good morning everyone.
>
>I'm building a new system. It's a Dell Poweredge 2650 which has an
>embedded SCSI controller with 2 HDD's attached. It also has in it an
>Adaptec 39160 PCI card, which I want to use for external SCSI devices.
>
>
>The plan is: Build the system (installing RedHat 7.3 + patches), and
>then plug in the external RAID array which presents itself as a single
>SCSI device.
>
>The problem is that when I plug in the external array, it takes over as
>"sda", shunting the disk with linux on it up to "sdb". This means that
>it can't find the root partition, so although it starts booting from the
>right place, it then kernel panics.
>
>I _could_ change the configuration of grub and also fstab so that the
>system boots happily from sdb, but then it is a problem if I remove the
>disk array. Since there will be a backup system with exactly the same
>hardware but no array, I need to be able to plug in the array and boot
>the system without any messing around changing grub and fstab.
>
>I investigated the PCI assignments of the SCSI controllers, and it shows
>that the external one has PCI address 1:08.0 and 1:08.1, while the
>internal one has 5:06.0 and 5:06.1. There are three PCI slots I can use
>for the external card, and they come up as 0:xx.x, 1:xx.x and 2:xx.x, so
>there is no way to get the internal SCSI controller to appear earlier on
>the PCI bus than the external one.

Internal/External SCSI controllers?  Do you mean one is built onto the 
Motherboard?

I think you need to ask your hardware manufacturer this one, it may be as 
simple as a jumper.  Personally, if I add PCI controllers to a motherboard 
I usually disable any on-board ones.  Better yet, don't buy motherboards 
with on-board SCSI.  If you must have two SCSI controllers then make them 
both add-on cards.

Scott.