Boot order with firewire 4.8-RELEASE

Matthew Seaman m.seaman at
Tue Jun 24 00:16:03 PDT 2003

On Mon, Jun 23, 2003 at 04:40:24PM -0700, Bill Campbell wrote:

> Be that as it may, when I booted the new kernel with an external firewire
> disk turned on, the new kernel detected the firewire disk before it did the
> SCSI on the adaptec controller, and naturally couldn't find a working
> system on it.  The system would boot with the firewire drive off allowing
> me to determine that I had screwed up the build.
> My basic question is how does one control the order devices are scanned
> during the boot process?  I would like to be sure that the system will come
> up after a power failure with no operator intervention if possible.

It's not really the order that the disks are discovered which matters
as such, but that the device numbers for your system disks depend on
the presence or absence of the external drive.

You can get round that by 'wiring down' the SCSI buses and devices in
your kernel config.  Eg. assume that your boot drive is at LUN 0 on an
Adaptec SCSI interface.  Then you could do:

    device     scbus0 at ahc0
    device     da0 at scbus0 target 0 unit 0

to ensure your boot disk always appears as da0. See the section 'SCSI
DEVICE CONFIGURATION' in /usr/src/sys/i386/conf/LINT for more details.



Dr Matthew J Seaman MA, D.Phil.                       26 The Paddocks
                                                      Savill Way
PGP:         Marlow
Tel: +44 1628 476614                                  Bucks., SL7 1TH UK
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 187 bytes
Desc: not available
Url :

More information about the freebsd-questions mailing list