Table15. Rear controller LEDs, controls, and connectors
LED Normal Status Problem Status
ServiceAction Allowed (OK to
Remove)
Off On
ServiceAction Required
(Fault)
Off On
CacheActive On - Data is in cache
Off - Caching is turned off. No
data in cache
Not applicable
Diagnostic On - Seven-segment LEDs
indicate diagnostic code
Off - Seven-segment LEDs
indicate enclosure ID
Not applicable
Heartbeat Blinking Off
Host Channel Speed - L1 See Table16 on page 107.
Host Channel Speed - L2 See Table16 on page 107.
Ethernet Link Speed On - 1 Gbps
Off - 100 Mbps
Not applicable

Note: The iSCSI ports have the same LEDs as the management Ethernet ports. As

with the Ethernet port LEDs, the iSCSI port LEDs represent link speed and

link activity.

Heartbeat
LED
Diagnostic
LED
Cache
active
LED
Service
action
required
LED
Service
action
allowed
LED
Hostchannel
speed- L1 LED
Drivechannel
port bypassLED
Drivechannel
speedLED
Ethernetlink
activityLED
Ethernetlink
speedLED
Hostchannel
speed- L2 LED
Figure71. LEDs, controls, and connectors of controllers with two standard Fibre Channel
host expansion channels and two optional iSCSI host expansion channels
106 IBM System Storage DS5020 Storage Subsystem: Installation, User’s, and Maintenance Guide