SAS HBA in a Sun X4250 - install issue

[Sean Walmsley]

I have a Sun X4250 (2U x86 with 16 drive backplane) server into
which I'm trying to install a Sun SG-XPCIE8SAS-I-Z 8-port internal
SAS HBA to connect up the disk backplane via the 2 pre-installed
8-way SAS cables (Note that this HBA is the LSI 3081 based card
and not the higher end Adaptec based unit).

My questions are:

  - Should I plug the card into PCI-E slot 0 or 1?
  - Should I attach both 8-way cables, just cable 0, or
    just cable 1 to the 16-disk backplane?

My confusion stems from conflicting references in the documentation:

PCI-E SLOT:
-----------
  - HBA install manual says to use PCI-E slot 0 if boot support
    is required.
  - Server service manual *SAYS* to use PCI-E slot 0 but
    *SHOWS* (figure) using slot 1
  - Server architecture manual says to use PCI-E slot 1
  - Sun system handbook top view of server shows using slot 1
  - cables are sized to make slot 1 the most convenient
  
SAS CABLES:
-----------
  - HBA install manual says to just use one SAS cable for 16
    disk servers.
  - Server service manual says to use both SAS cables.

We've used this card in a Sun X4450 (8 drive backplane) previously
with the HBA installed in slot 0 and both cables used. I don't know
why Sun would call for half as many cables for a server with
twice as many drives.

If you've received this configuration configured by Sun, or
if you've successfully implemented it yourself, I'd appreciate your
feedback.

Thanks!

Sean Walmsley

=================================================================
Sean Walmsley        sean at fpp . nuclearsafetysolutions dot com