IBM DS3500, Installation, User & Maintenance Manual

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SAS link service action LED (amber)
When this LED is lit, it indicates a problem with the SAS link that requires
service action. The normal condition of this LED is off.
SAS link up LED (green)
When this LED is lit, it indicates that the link is established between the
controller and a host. When this LED is flashing, it indicates activity on the
link. When this LED is off, no link is established.
Seven-segment numeric display LEDs
The seven-segment numeric display LEDs provide information about enclosure
identification and diagnostics. Figure 74 shows the numeric display LEDs.
When you turn on the power to the storage or expansion enclosure, the numeric
display LEDs cycle though various codes as the controller or ESM firmware starts
to boot.
When the storage subsystem is operating normally, the numeric display shows the
enclosure identification (enclosure ID) of the storage subsystem.
If an error has occurred and the Needs Attention LED is on, the numeric display
shows diagnostic information. The numeric display indicates the information is
diagnostic by illuminating an LED that appears as a decimal point between the
display numbers. The diagnostic LED tuns off when the numeric display shows the
enclosure ID. The numeric display shows various diagnostic codes as the
enclosures perform the startup process after each power cycle or reset. After
diagnostics are complete, the current storage subsystem enclosure ID is displayed.
Diagnostic codes in the form of Lx or Hx, where x is a hexadecimal digit, indicate
storage subsystem state information. In general, these codes are displayed only
when the storage subsystem is in a non-operational state. The storage subsystem
might be non-operational due to a configuration problem (such as mismatched
types), or it might be non-operational due to hardware faults. If the storage
subsystem is non-operational due to system configuration, the storage subsystem
Needs Attention LED is off. If the storage subsystem is non-operational due to a
SAS link service
action
(amber) LED
SAS link up LED
Figure 73. SAS host port adapter LEDs
Figure 74. Numeric display LEDs
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System Storage DS3500 and EXP3500: Installation, User’s, and Maintenance Guide