Restoring Power After An Unexpected Shutdown - IBM DS4800 User, Installation And Maintenance Manual

5. Check the back of the storage subsystem, and verify that the Cache Active LED
6. Check the LEDs on the storage expansion enclosures to verify that all Drive
7. Turn off the AC power switch on the back of each controller in the storage
8. Turn off both power switches on the back of each storage expansion enclosure
9. After you perform the necessary maintenance procedures, turn on the power

Restoring power after an unexpected shutdown

The storage subsystem might shut down unexpectedly under any of the following
conditions:
Attention:
v The internal temperature of the storage subsystem exceeds the maximum
v In the DS4800 Storage Subsystem, the right power supply-fan unit is linked to
v There is a general power failure or a loss of power to the unit.
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IBM System Storage DS4800 Storage Subsystem: Installation, User's, and Maintenance Guide
c. When the recovery procedure is completed, select Recheck in the Recovery
Guru. This action reruns the Recovery Guru to ensure that the problem has
been fixed.
d. If the problem has not been fixed, contact your IBM service representative.
Do not turn off power until all problems are corrected.
is off.
If the Cache Active LED is on steady, the cache contains data. Wait for the data
to clear from cache memory before turning off the power.
Active LEDs are on steady (not blinking).
If one or more LEDs are blinking, data is being written to or from the drives.
Wait for all Active LEDs to stop blinking.
subsystem. (Figure 67 on page 89 shows the location of the AC power switch
on a controller.)
Note: Until the power switch on each controller is turned off, power still remains
turned on for the both controllers; therefore, the seven-segment display
on each controller stays on until the power switch on each controller is
turned off.
in the configuration.
using the procedure in "Turning on the storage subsystem" on page 97.
There might be a loss of access to data in each of the following cases.
operating temperature (an over-temperature condition).
If both power supply-fans fail or are unable to maintain an internal temperature
below 70° C (158° F), one or both of the power supplies in the storage
subsystem will shut down. If both power supply-fans shut down, the unit is
inoperable.
The DS4000 Storage Manager client warns you if the temperature of the unit is
rising before it has risen sufficiently to shut down the power supplies. The first
warning comes when the storage subsystem internal temperature exceeds 45° C
(113° F). The storage subsystem shuts down if the temperature rises to 70° C
(158° F).
Controller A, and the left power supply-fan unit is linked to Controller B. If one
power supply-fan unit has shut down and the controller that is linked to the other
power supply-fan unit is removed, the DS4800 will be inoperable. To increase
protection against power loss, always make sure that both power supply-fan units
are plugged in and are operational.