7914DS3KIntro_081410alw.fm Draft Document for Review March 28, 2011 12:24 pm
16  IBM System Storage DS3500: Introduction and Implementation Guide
In dual controller configurations, the controller on the left is A and the right is B, when viewed 
from the rear of the subsystem. Dual controller configurations offer redundant access to disk 
storage. In case of controller or I/O path failure, the other controller will continue to provide 
access to disk drives. 
All DS3500 RAID controllers have connectors for the following connections built into them: 
ň° Two 6Gbps SAS host server attachment ports 
ň° Drive side 6Gbps SAS expansion port 
ň° Ethernet management port 
ň° Serial management port 
The RAID controllers and two redundant power supply modules are installed in the rear of the 
subsystem as shown in Figure 2-5 below.
Figure 2-5   DS3500 controller subsystem rear view
In Figure 2-5, the controller modules are in the upper half of the subsystem and the power 
supply modules are in the lower half.
Power Supply
The DS3500 power supply module is a 585 Watt DC power supply. It is auto ranging 
100-240VAC input capable. As shown in Figure 2-5 the power supply provides LED indicators 
for the following states (starting from left):
ň° Standby power LED (green) - Currently this LED is not used.
ň° DC power LED (green) - When this LED is lit, it indicates that the DS3500 is turned on and 
is supplying both 5-volt and 12-volt dc power.
ň° OK to remove LED (blue) - When this blue LED is lit, it indicates that it is safe to remove 
the power supply.
ň° Fault LED (amber) - When this amber LED is lit, it indicates that a power supply or fan has 
failed or that a redundant power supply is not turned on.
ň° AC power LED (green) - When this green LED is lit, it indicates that the storage subsystem 
is receiving ac power
Host interface cards
As mentioned earlier the DS3500 comes with two SAS host attachment ports built into the 
controller modules. Additional host server connectivity is supported through the use of an 
optional daughter card (shown in Figure 2-6 on page 17). This interface card can provide for 
one of the following to be added to the DS3500:
ň° Additional four SAS ports
ň° Eight 1Gbit iSCSI ports (four per controller)
ň° Eight FC ports (four per controller)