On Tue, Jan 16, 2001 at 10:10:23AM -0800, Brian Buhrow wrote:
> 	Hello folks.  We're trying to build a fairly large RAID array of IDE
> disks on a NetBSD 1.4.2 system using Promise Ultra DMA PCI IDE controllers.
>  We've got 3 Promise cards with 4 drives each, for a total of 12 drives for
> the array, plus the onboard Motherboard IDE for the boot disk.  The machine
> seems to boot fine, but after a few minutes of operation, all activity
> comes to a halt and everything seems to hang.  While this arrangement of
> drives and cards seems reasonable, I have never tried to run 7 IDE busses
> in one machine at the same time.  Are there limitations in the drivers,
> that people are awareof, which could hamper our effort on this project?
> Would 1.5 work better in this respect?  Does anyone have any experience
> with trying to pack so many drives in one case?

I've actually got problems with 4 fast disks on channels: machine hang
under heavy I/O (hard hang: no kernel messages, can't enter ddb -
I suspect PCI lockup) The same machine was happy with 2 slower disks as master.
Keeping only one disk per channel (at the expence of a promise Ultra/33 :)
Solved the problem.

7 IDE busses shouldn't be a problem, but 2 disks per channel migth.
Also I can't see how you'll put 12 disks in a box; you may exeed the max cable
length for UltraDMA.

--
Manuel Bouyer <bouyer@antioche.eu.org>
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