No docs, but you want as many ports as possible for maximum throughput.
Officially, you can put three drives per HBA port (through a switch, not
Y cables). I tell customers that a maximum of two drives per HBA port
will make them a LOT happier; three LTO4 drives could saturate the
connection, and that's a bad thing with tape.
 
--
Mark Stapleton (mark.stapleton AT cdw DOT com)
CDW Berbee
System engineer
7145 Boone Avenue North, Suite 140
Brooklyn Park MN 55428-1511
763-592-5963
www.berbee.com
 

> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf
> Of Larry Peifer
> Sent: Thursday, November 20, 2008 12:49 PM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: [ADSM-L] IBM 3200 Tape Library SAS adapters
> 
> We are in the process of purchasing an IBM 3200 Tape Library with 4 -
> LTO4
> half-height SAS drives.  Our IBM sales rep and tech support rep are
> telling
> us that we need 4 - 5912 HBAs, one for each drive, to support this
> configuration in our IBM 9117-MMA (p570) host.
> 
> From our review of the tech specs it looks like the 5912 Adapter
(PCI-X
> DDR
> Dual -x4 SAS Adapter) should be able to support all four SAS tape
> drives
> from one card using 2- YO cables in the same way it can support 4 disk
> drives.  Can anyone point us to someone or some docs that can give us
> more
> information.
> 
> Larry Peifer
> San Onofre Nuclear Generating Station
> AIX System Admin
> TSM system Admin