Specifications

98 IBM Power 770 and 780 Technical Overview and Introduction
For detailed information about the SAS cabling, see the serial-attached SCSI cable
planning documentation:
http://publib.boulder.ibm.com/infocenter/powersys/v3r1m5/index.jsp?topic=/p7had/p7
hadsascabling.htm
2.11.3 TotalStorage EXP24 disk drawer and tower
The TotalStorage EXP24 is available as a 4 EIA unit drawer and mounts in a 19-inch rack
(#5786). The front of the IBM TotalStorage EXP24 Ultra320 SCSI Expandable Storage Disk
Enclosure has bays for up to 12 disk drives organized in two SCSI groups of up to six drives.
The rear also has bays for up to 12 disk drives organized in two additional SCSI groups of up
to six drives, plus slots for the four SCSI interface cards. Each SCSI drive group can be
connected by either a Single Bus Ultra320 SCSI Repeater Card (#5741) or a Dual Bus
Ultra320 SCSI Repeater Card (#5742). This allows the EXP24 to be configured as four sets
of six bays, two sets of 12 bays, or two sets of six bays plus one set of 12 bays.
The EXP24 features #5786 and #5787 have three cooling fans and two power supplies to
provide redundant power and cooling. The SCSI disk drives contained in the EXP24 are
controlled by PCI-X SCSI adapters connected to the EXP24 SCSI repeater cards by SCSI
cables. The PCI-X adapters are located in the Power 740 system unit or in an attached I/O
drawer with PCI-X slots.
The 336 system maximum is achieved with a maximum of 24 disks in a maximum of 14
TotalStorage EXP24 disk drawers (#5786) or 14 TotalStorage EXP24 disk towers (#5787).
2.11.4 IBM TotalStorage EXP24
The IBM 7031 TotalStorage EXP24 Ultra320 SCSI Expandable Storage Disk Enclosure
supports up to 24 Ultra320 SCSI Disk Drives arranged in four independent SCSI groups of up
to six drives or in two groups of up to 12 drives. Each SCSI drive group can be connected by
either a Single Bus Ultra320 SCSI Repeater Card or a Dual Bus Ultra320 SCSI Repeater
Card, allowing a maximum of eight SCSI connections per TotalStorage EXP24.
The IBM 7031 Model D24 (7031-D24) is an Expandable Disk Storage Enclosure that is a
horizontal 4 EIA by 19-inch rack drawer for mounting in equipment racks.
The IBM 7031 Model T24 (7031-T24) is an Expandable Disk Storage Enclosure that is a
vertical tower for floor-standing applications.
Note: IBM plans to offer a 15-meter, 3 Gb bandwidth SAS cable for the #5913 PCIe2
1.8 GB Cache RAID SAS Adapter when attaching the EXP24S Drawer (#5887) for large
configurations where the 10 meter cable is a distance limitation.
The EXP24S Drawer rails are fixed length and designed to fit Power Systems provided
racks of 28 inches (711 mm) deep. EXP24S uses 2 EIA of space in a 19-inch wide rack.
Other racks might have different depths, and these rails will not adjust. No adjustable
depth rails are orderable at this time.
Note: The EXP24S SCSI disk drawer is an earlier technology drawer compared to the later
SAS EXP12S drawer. It is used to house existing SCSI disk drives that are supported, but
that are no longer orderable.