HP DL585 ProLiant DL585 Generation 2 Server User Guide - Page 48

Battery-backed write cache

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Battery-backed write cache The HP BBWC protects against hard boot, power, controller, and system board failures. The server supports the following battery-backed options: • 256-MB BBWC option • 512-MB BBWC option The BBWC consists of two parts: a battery pack and a storage cache module. 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 after the server loses power. The NiMH batteries in the battery pack are continuously recharged through a trickle-charging process whenever the system power is on. 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 upgrade the BBWC: 1. Close all applications, and power down the server (on page 27). This procedure flushes all data from the cache. 2. Extend the server from the rack ("Extending the server from the rack" on page 27). 3. Remove the access panel ("Removing the access panel" on page 28). 4. If the existing cache is connected to a battery, observe the BBWC Status LED ("Battery pack LEDs" on page 17). o If the LED is blinking every 2 seconds, data is still trapped in the cache. Restore system power, and repeat the previous steps. Hardware options installation 48

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Hardware options installation 48
Battery-backed write cache
The HP BBWC protects against hard boot, power, controller, and system board failures. The server
supports the following battery-backed options:
•
256-MB BBWC option
•
512-MB BBWC option
The BBWC consists of two parts: a battery pack and a storage cache module.
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 after the server loses power.
The NiMH batteries in the battery pack are continuously recharged through a trickle-charging process
whenever the system power is on.
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 upgrade the BBWC:
1.
Close all applications, and power down the server (on page
27
). This procedure flushes all data
from the cache.
2.
Extend the server from the rack ("
Extending the server from the rack
" on page
27
).
3.
Remove the access panel ("
Removing the access panel
" on page
28
).
4.
If the existing cache is connected to a battery, observe the BBWC Status LED ("
Battery pack LEDs
" on
page
17
).
o
If the LED is blinking every 2 seconds, data is still trapped in the cache. Restore system power,
and repeat the previous steps.