PE 4600: Splitting backplane - daughter card, please help!

Matt Domsch Matt_Domsch at
Fri Oct 17 12:20:01 CDT 2003

> PE 4600 (system spec given below):
> I am planning to add a daughter card to split the backplane to 2x8.

2x4 instead of 1x8, yes.

> With this I was told I will be able to setup two arrays separate for
> each channel in RAID. I wanted to put 3x18G 10K hard disk in one array
> and in another two separate 146G hard disk containers. The main purpose
> of this is to get a better computational performance with the 3x18G 10K
> hard disk array and use the separate 146 hard disks for file storage. I
> would like to know if I am in the correct path or am I doing something
> wrong?

Looks good so far.

> Also I was wondering will my PE 4600 will have two SCSI channels so that
> I can put the two arrays in different channel.

Yes, it has 2 SCSI channels, or 2 RAID channels, or one SCSI channel and 
one RAID channel, however you wish.

> If so I want to know if this can be done with bios setup or does it
> require any physical connections or cabling to be done.

Yes, it is done through BIOS setup, and you've got to have the cables 
right.  There are 2 68-pin wide SCSI connectors on the motherboard, and 2 
short cables running from those to the SCSI backplane (when in split 
backplane mode with the daughtercard), one cable to each side of the 
backplane, and each side has 4 disks.

> I am confused with the connection between SCSI and RAID controller so if
> you could help me understand better it would be great.

The RAID controller and the SCSI controller are really inter-related - 
they both use the same aic7xxx SCSI chip and connectors, and you can 
configure each channel for either SCSI mode or RAID mode.

For the rest, you really need to discuss with a Systems Consultant.  Your 
salesperson can assist.

> 1  60EPW  Printed Wiring Assy, Backplane, Jaguar, 1X8, ULT3, Slide

This is the SCSI backplane.  You aren't ordering the daughtercard to make 
it a 2x4 split backplane with this config right now.

> 1  9M912   Assembly, Card (Circuit), PERC3-DC, INTEL-BE

This is an add-in PERC3/DC RAID card, not the onboard RAID I believe.  Is
that what you want?  This card does have 2 channels also, so you can have 
your 146GB disks on one channel and your other disks on the second 
channel, both sides connected to the backplane.

> 2  4R318   Hard Drive, 146GB, SCSI (Small Computer Systems Interface), U320, 10K, 80P, FJT
> 1  1M214   Assembly, Cable, Twisted Pair, Hard Drive, 2DROP, Enclosure

This is the cable running from your add-in RAID card to the enclosure, 
with 2 disks attached to it.  But it's only one cable, you need 2 do to 
the split backplane thing.

You should consult with your Systems Consultant, this doesn't quite look 
like what you indicate you want.  You need the daughtercard, and may not 
need the add-in PERC3/DC card - that's entirely up to you.


Matt Domsch
Sr. Software Engineer, Lead Engineer
Dell Linux Solutions
Linux on Dell mailing lists @

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