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HP ProLiant DL380 Generation 4 Server Reference and Troubleshooting Guide

Battery-Backed Write Cache Enabler Option

Along with the memory module, the Battery-Backed Write Cache Enabler, also
known as the battery module, provides transportable data protection, increases
overall controller performance, and maintains any cached data for up to 72 hours.
The NiMH batteries in the battery module are continuously recharged through a
trickle-charging process whenever the system power is on. Under normal
operating conditions, the battery module lasts for 3 years before replacement is
necessary.

For information on battery module LEDs, refer to "Battery-Backed Write Cache
Enabler LEDs."

CAUTION: To prevent damage to the equipment or server

malfunction, do not add or remove the battery module while an array
capacity expansion, RAID level migration, or stripe size migration is in
progress.

CAUTION: After the server is powered down, wait 15 seconds

and then check the amber LED before unplugging the cable from the
battery module. If the amber LED blinks after 15 seconds, do not
remove the cable from the battery module. The battery module is
backing up data, and data will be lost if the cable is detached.

IMPORTANT: The battery module may have a low charge when
installed. In this case, a POST error message is displayed when the
server is powered up, indicating that the battery module is temporarily
disabled. No action is necessary on your part. The internal circuitry
automatically recharges the batteries and enables the battery module.
This process may take up to 4 hours. During this time, the array
controller will function properly, but without the performance advantage
of the battery module.

NOTE: The data protection and the time limit also apply if a power
outage occurs. When power is restored to the system, an initialization
process writes the preserved data to the hard drives.

To install the Battery-Backed Write Cache Enabler:

1. Power down the server ("Powering Down the Server" on page