HP Surestore Disk Array 12h - And FC60, Advanced User'S Manual, Page: 43 / 466

Array Controller Enclosure Components
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Each power supply is equipped with a power switch to disconnect power to the supply.
Turning off both switches turns off power to the controller. This should not be performed
unless I/O activity to the disk array has been stopped, and the write cache has been flushed
as indicated by the Fast Write Cache LED being off.
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The controller power switches should not be turned off unless all I/O activity
to the disk array has been suspended from the host. Also, power should not be
turned off if the Fast Write Cache LED is on, indicating that there is data in
the write cache. Wait until the Fast Write Cache LED goes off before shutting
off power to the disk array.
Each power supply is equipped with a power-on LED indicator. If the LED is on (green) the
supply is providing dc power to the controller. If the LED is off, there is a malfunction or
the power has been interrupted. The system Power Fault LED on the front of the controller
enclosure works in conjunction with the Power Supply LEDs. If both power supplies are
on, the system Power Fault LED will be off. If either power supply is off or in a fault state,
the system Power Fault LED goes on. When both power supplies are off or not providing
power to the enclosure, the system power LED on the front of the controller enclosure will
be off.
Power Supply Fan Module
Like the controller fan, the power supply fan module ( Figure 15 ) is a single removable unit
that contains dual cooling fans. Dual fans provide a redundant cooling system to both
power supply modules. If one fan fails, the other will continue to operate. A single fan will
provide sufficient air circulation to prevent the power supplies from overheating until the
entire power supply fan module can be replaced. The power supply fan module plugs
directly into a slot on the back of the controller enclosure, between the power supplies. It
has a locking lever that allows it to be unlatched and removed.
The power supply fan can be hot swapped, provided the exchange is performed within 15
minutes. This time limit applies only to the total time during which the fan is out of the
enclosure, beginning when you remove the failed unit and ending when you re-seat the new
one. This does not include the time it takes you to perform this entire procedure (including
checking LEDs).