HP ProLiant DL360 G4p Server - Manual (Page 53)

Hardware Options Installation 53
Battery-Backed Write Cache Enabler Option
The Battery-Backed Write Cache Enabler, also called the battery pack, works
with the cache module to provide transportable data protection, increase overall
controller performance, and maintain any cached data for up to 72 hours. The
NiMH batteries in the battery pack are continuously recharged through a trickle-
charging process whenever the system power is on. Under normal operating
conditions, the battery pack lasts for 3 years before replacement is necessary.
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.
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 25 ).
2. Extend the server from the rack, if applicable ("Extending the Server from
the Rack" on page 26 ).
3. Remove the access panel ("Removing the Access Panel" on page 27 ).
4. Align the battery module over the quarter-turn fasteners.