HP ProLiant DL380 G3, User Manual

Page: 77 / 164

Hardware Options Installation 77
Battery-Backed Write Cache Enabler Option
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 (on page 34)" on the Documentation CD.
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 applies 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 37).
2. Extend the server from the rack, if applicable ("Extending the Server from
the Rack" on page 38).
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