Two SCSI-adapters, HD booting from the wrong device

[Thomas Schweikle]

Hi!

I have configured:

Primary SCSI: Adaptec 2940, PCI SCSI adapter
Secondary SCSI: Adaptec 79xx, onboard SCSI adapter

the primary adapter is connected to
- id:0 SCSI-I, HD
- id:3 SCSI-I, CD-ROM
- id:4 SCSI-I, CD-RW

the secondary adapter is connected to
- id:0 SCSI-II, LVD only HD

The system boots from the first HD on the primary adapter. Then the kernel
loads. Shortly after it doesn't find its root. It is asking to give the
root slice. I am typing in: "ufs:/dev/das1a". But this again leads to an
error number 6: root not found.

The kernel assigns scbus1 to the primary adapter, scbus0 to the secondary,
while the BIOS assigns scbus0 to the primary, scbus1 to the secondary one.

I have tried to change BIOS assignments, but this rendered the system
unbootable. Removing the LVD only HD from the system makes it boot
seamlessly.

Trying to wire the whole thing, to make the kernel assign scbus0 to the
primary adapter, scbus1 to the secondary:
hint.scbus.0.at="ahc1"
hint.da.0.at="scbus0"
hint.da.0.target="0"
hint.da.0.unit="0"

hint.scbus.1.at="ahc0"
hint.da.1.at="scbus1"
hint.da.1.target="0"
hint.da.1.unit="0"

But this leads to the same error as above: mountroot doesn't find the root
device. Trying "ufs:/dev/da0s1a" or "ufs:/dev/da1s1a" just give error
number 6.

Again: removing the HD on the secondary bus makes the system boot again
without errors.

Next I tried to recompile the kernel to load scbus1 to ahc0 and scbus0 to
ahc1:

device ahc0;
device ahc1;

device scbus1 at ahc0;
device scbus0 at ahc1;

but I did not have success, since the old SCSI-I disk does not have enough
free space to recompile the kernel. Any idea, how I can make the system
boot, with both disks online and accessible, so I can do, what I'd like to,
mount the new LVD only HD, moving some part to new slices, adding space to
the system?

-- 
Thomas