Rear panel LEDs

The Disk Enclosure rear panel LEDs are described.

Power supply unit

AC-DC power is provided by up to two auto-ranging power supply modules (PSUs). Cooling is provided by four separate cooling fans and two controller module fans. The IOM provides power and LED control. Also see the System airflow section for optimal cooling within the enclosure(s).

2,000W PSU

The 2,000W PSU voltage operating range is nominally 200V–240V AC, and operates at 50–60 Hz input frequency. In the figure below, the dimetric rear orientation shows the PSU aligned for insertion into either PSU slot located on the enclosure rear panel.

Table 1. LEDs - 2000W PSU - rear panel
Module LED	LED behavior states
PSU Status LED (Bitonal)	PCM OK (Green)	PSU fault/failure (Amber/blinking amber)	Power off (Off)

Multiple power supply unit modules

The 4U storage system includes two PSUs which provide redundant power control for the system so that if one module fails, the other maintains the power supply, and enclosure operation is not affected while you replace the faulty module.

PSUs are hot-pluggable, and replacement should only take a few seconds to do. Replacement must be completed as soon as possible after the removal of the defective PSU to avoid a thermal exception. The replacement procedure should be completed within an absolute maximum of three minutes.

Important:

Operation of the enclosure with any modules missing will disrupt the airflow, and the disks will not receive sufficient cooling. It is essential that all slots are fitted with PSUs prior to powering on the enclosure.

System fan module

Enclosure cooling is provided by four system fan modules used in combination with two controller channel fan modules. The IOM provides fan and LED control. This section describes system fan modules. See also the Controller channel fan module section.

LEDs Fan — Figure 2. LEDs - system fan module - rear panel

Table 2. LEDs - system fan module - rear panel
Module LED	LED behavior states
System Fan Status LED	System Fan OK (Off)	Fan fault/ID (amber/blinking amber)	Power off (Off)

Multiple system fan modules

The Disk Enclosure includes four system fan CRUs which provide redundant cooling for the system, so that if one module fails, the others maintain airflow circulation, and enclosure operation is not affected while you replace the faulty module. Within this CRU module, if one of the two internal rotors fails, then a fault occurs, indicating module failure. A dual rotor failure is reported as a dual-fault.

System fans are hot-pluggable, and replacement should only take a few seconds. Replacement must be completed as soon as possible after the removal of the defective system fan to avoid a thermal exception. The replacement procedure should be completed within an absolute maximum of 2 minutes for this CRU module.

Important:

Operation of the enclosure with any modules missing will disrupt the airflow, and the disks will not receive sufficient cooling. It is essential that all slots are fitted with system fans prior to powering on the enclosure.

System airflow

The system must be operated with low pressure rear exhaust installation. Back pressure created by rack doors and obstaclesis not to exceed 5 pascals (0.5mm water gauge). The cooling system provides sufficient capacity to ensure that maximum temperatures are not exceeded.

Important:

The environment in which the enclosure operates must be dust-free to ensure adequate airflow.

Expansion module

IOMs are used in IBM COS Medium and Large Disk Enclosures 12Gb/s storage enclosures.

The figure below is a dimetric rear orientation that shows a pictorial view of an expansion module. You would revolve the module by 90º along its longitudinal axis, before inserting it into the IOM slot, as shown in Figure 1 and the figure in the section Removing the IOM.

Expansion module rear — Figure 3. Expansion module - dimetric rear orientation

Each controller module maintains VPD (Vital Product Data) in EEPROM devices, and are interconnected by I2C buses on the mid-plane. In this way, the modules can discover the type and capabilities of the partner module(s), and vice versa, within the enclosure. An enclosure system fault occurs when incompatible configurations are detected. The replacement procedure should be completed within an absolute maximum of three minutes.

Important:

For a description of EBOD canister LEDs, see Figure 4.

12Gb/s expansion module LEDs

The figure and table below provide a description of the expansion module that installs into the rear panel of an COS Medium/Large JBOD expansion enclosure. The module is shown resting on its base. To install the module into one of the IOM slots located on the enclosure rear panel, you would first revolve the module by 90º along its longitudinal axis, before inserting it into a slot as shown in Figure 1. Showing expansion modules separately from the enclosure enables improved clarity in identifying the component items called out in the diagrams and described in the companion tables within the figure/table ensembles.

12Gb/s expansion module rear — Figure 4. LEDs: 12Gb/s Expansions module - rear panel

Table 3. LEDs: Expansion module - rear panel
LED	Description	Definition
1	12Gb SAS Fault¹	Off - No fault detected. Amber - A fault has been detected on the port.
2	12Gb SAS Link Status and Activity¹	Off - No link detected. Green - The port is connected and the link is up. Blinking green - The link has I/O activity.
3	Fault	Off - The expansion module is operating normally. Amber - A fault has been detected or a service action is required.
4	Power OK	Green - The expansion module is operating normally. Blinking green - System is booting. Off - The expansion module is powered off.
5	Ethernet Port Link Speed²	Ethernet managing is not supported at this time
6	Ethernet Port Link/Active Status²	Ethernet managing is not supported at this time

¹ This LED description applies to all 12Gb SAS ports (Port 0 through 3).
² This LED description applies to both management ports (Port 0 and Port 1).