IBM Power Systems 775 Manual page 64

Figure 1-40 Storage drawer top view
The disk enclosure is a SAS storage drawer that is specially designed for the IBM Power 775
system. The maximum storage capacity of the drawer is 230.4 TB, distributed over 384 SFF
DASD drives logically organized in eight groups of 48.
The disk enclosure feature two mid-plane boards that comprise the inner core assembly. The
disk drive carriers, port cards, and power supplies plug into the mid-plane boards. There are
four Air Moving Devices (AMD) in the center of the drawer. Each AMD consists of three
counter-rotating fans.
Each carrier contains connectors for four disk drives. The carrier features a solenoid latch that
is released only through a console command to prevent accidental unseating. The disk
carriers also feature LEDs close to each drive and a gold capacitor circuit so that drives are
identified for replacement after the carrier is removed for service.
Each port card includes four SAS DDR 4x ports (four lanes at 6 Gbps/lane). These incoming
SAS lanes connect to the input SEC, which directs the SAS traffic to the drives. Each drive is
connected to one of the output SECs on the port card with SAS SDR 1x (one lane @ 6 Gbps).
There are two port cards per STOR. The first Port card connects to the A ports of all 48 drives
in the STOR. The second Port card connects to the B ports of all 48 drives in the STOR. The
port cards include soft switches for all 48 drives in the STOR (5 V and 12 V soft switches
connect and interrupt and monitor power). The soft switch is controlled by I2C from the SAS
Expander Chip (SEC) on the port card.
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IBM Power Systems 775 for AIX and Linux HPC Solution
Front View
Of STOR
STOR8 STOR7
2 Port 2 Port
Cards Cards
12 Carriers 12 Carriers
(36 Drives) (36 Drives)
Heat Exchanger
STOR1 STOR2
2 Port 2 Port
Cards Cards
12 Carriers 12 Carriers
(36 Drives) (36 Drives)
STOR6 STOR5
2 Port 2 Port
Cards Cards
12 Carriers 12 Carriers
(36 Drives) (36 Drives)
STOR3 STOR4
2 Port 2 Port
Cards Cards
12 Carriers 12 Carriers
(36 Drives) (36 Drives)