SCSI device ordering (was Re: 2.1.93..)

Andrew J. Anderson (andrew@db.erau.edu)
Fri, 17 Apr 1998 09:07:41 -0400 (EDT)


> 3. BIOS uses its internal code to select a drive to be the boot
> drive. This may have been set as one of the ROM BIOS options.

This is the whole issue -- this order is undefined. I have access to a
SMP machine with 1 BusLogic and 2 NCR SCSI controllers that was a royal
BITCH to setup because we had to get the *order* of the cards in the PCI
slots _and_ the BIOS PCI IRQ mappings right for it to boot off the correct
drive and correctly initialize all of the cards.

It would be a *TOTAL* nightmare on that system to have 'automagically'
find the non-root fs's once we boot, assuming that we were able to find
the root fs! And with as much use as that system gets, I don't want to
even try:

8:46am up 8 days, 11 min, 2 users, load average: 9.29, 8.13, 7.80

Geez, and that's with 2 200Mhz PPro's...

Until the ext2 mount can handle using UUID to associate devices and the
filesystems they should map to (akin to what SUN does with their SSA
drives), I'd rather keep the BIOS ordering. There are just too many
things that aren't ready for that, including sys admins. This is way too
late in the development cycle to break something this fundamental.

Andrew

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Andrew Anderson http://amelia.db.erau.edu/~andrew/
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