IBM DS4800 User, Installation And Maintenance Manual page 186

Table 24. DS4800 Symptom-to-FRU index (continued)
Problem
indicator Component
One or more Controller Cache
Green LEDs off LED off
Battery LED off
and power
supply-fan Power
LED off
L1 and L2 (Link
Speed) LEDS for
a host port
L1 and L2 (Link
Speed) LEDs of
drive port
164
IBM System Storage DS4800 Storage Subsystem: Installation, User's, and Maintenance Guide
Possible cause
Caching is not enabled or
was disabled because:
v The cache memory in
controllers A and B is
mismatched.
v The battery is charging or
performing a diagnostic
test.
v One of the cache backup
battery packs has failed.
Or, there are no I/Os being
sent to the DS4800.
The battery is missing
Fibre-channel cable is not
attached to the DS4800 host
port or the FC device that
should be connected to this
DS4800 host port.
No FC signal detected
SFP module failure or SFP
module not seated properly
Possible solutions
Enable write-caching using the DS4000 Storage
Manager client program.
Or:
v Use the DS4000 storage manager client
program to verify the cache memory for both
controllers.
v The DS4800 performs battery diagnostic tests
and recharges every 25 hours. Write caching is
disabled during the test and will be enabled
automatically after the test completes. The test
duration time varies depending on the
recharging requirement, but the duration should
be less than 15 minutes.
v Replace the failing battery.
If there are no I/Os being sent to the DS4800,
generate I/Os to send to the DS4800.
Verify that the battery is missing. All DS4800s are
shipped with both cache battery packs installed.
Call IBM support if a cache battery pack is
missing and you did not remove any of the cache
battery packs from the DS4800.
Connect the fibre-channel cable to the enclosure
port; check other connections.
Reattach the SFPs and fibre-channel cables.
Verify that the fibre channel cables are in good
condition and that there are no cable management
issues (such as using plastic ties to wrap the
cables or bending the cable loops to less than 1.5
inches).
Verify the SFPs are working properly. Use the
wrap-plug coupler kit that ships with the DS4800
and the wrap-plug instructions in the DS4000
Problem Determination Guide.
Replace input and output SFPs or cables as
necessary.
Reseat the SFP.
Verify the SFPs are working properly. Use the
wrap-plug coupler kit that ships with the DS4800
and the wrap-plug instructions in the DS4000
Problem Determination Guide.
Replace SFPs as necessary.