HP ProLiant DL380 G4 Server - Manual (Page 54)

Hardware options installation 54
Battery-backed write cache option
NOTE: This feature applies only to SCSI models.
Along with the cache module, the battery pack provides transportable data protection, increases overall
controller performance, and maintains 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.
For information on BBWC LEDs, refer to "Battery-backed write cache LEDs (on page 25 )" and "Battery-
backed write cache LED statuses (on page 26 )."
CAUTION: To prevent a server malfunction or damage to the equipment, do not add or remove the battery
pack 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 cache module. If the amber LED blinks after 15 seconds, do not remove the
cable from the cache module. The cache module is backing up data, and data is lost if the cable is
detached.
IMPORTANT: The battery pack might 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 pack is temporarily
disabled. No action is necessary on your part. The internal circuitry automatically recharges the batteries
and enables the battery pack. This process might take up to four hours. During this time, the cache module
functions properly, but without the performance advantage of the battery pack.
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 BBWC:
1. Power down the server (on page 27 ).
2. Extend the server from the rack, if applicable (" Extend the server from the rack " on page 28 ).
3. Remove the access panel (" Removing the access panel " on page 29 ).
4. Remove the front fan bracket (" Front fan bracket " on page 53 ).
5. Remove the PCI riser cage (" Removing the PCI riser cage " on page 57 ).
6. Connect the cable to the cache module and install the cache module.