Problem with multiple scsi adapters and drive assignments

Erik Trulsson ertr1013 at
Tue Mar 18 16:46:00 PDT 2008

On Tue, Mar 18, 2008 at 06:37:30PM -0400, John A. wrote:
> I've searched all over (not totally exhaustive, but close) and can't find an
> answer that I thought would have come up before.  Basically, I need to
> change the order that the kernel assigns drive names on bootup.
> It all started out with an old Intel server board with NCR/Symbios scsi
> builton.  I added a QLogic QLA2100 fibre controller and everything was fine
> except that it was a little slow and couldn't hold enough ram.  I took
> another (newer) Intel server board and put it in the case.  This board has
> an Adaptec AIC7896 builtin.  My custom kernel didn't have the aic driver so
> I took the opportunity to upgrade to 7.0 and built a new kernel.  Everything
> was fine until I turned on the external fibre chassis and found that my da0
> became da7.  The board is in a rack-mount case so I cant put the QLA into a
> different slot and the bios doesn't have any way to change irq settings on
> the pci slots.
> I my mind, the logical answer is to tell FBSD to scan ahc0 before isp0.
> Through all my searching through docs and the mailing list archives, I can't
> find any mention of how to do this.  I did find one mention of turning off
> the bios on the offending scsi card (it was a system with 2 Adaptecs).  Been
> there, tried that, didn't work.  Feel free to slap my face and call me
> stupid as long as you point my to the proper info if I somehow missed it.
> Here are the relevant parts of dmesg if that helps (I didn't include the
> drives themselves since I can't get it boot with the external chassis turned
> on):

The solution is not to change the order in which things are probed, but to
hard-wire which name is assigned to which disk.
See the SCSI(4) manpage for information on how to do this by setting hints
in /boot/device.hints.

<Insert your favourite quote here.>
Erik Trulsson
ertr1013 at

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