8 Battery Backup Unit (BBU)
The Battery Backup Unit (BBU) is an optional subsystem that provides security against data loss during power failures. Power is provided to cache memory only so that when the system restarts, write cached data may be written to the disk. The system detects when the power is failing and puts the cache memory into
8.1Data Hold Time
The exact time the BBU will maintain the data in the cache memory is dependent on the specific cache memory installed, the condition of the battery, the amount of charge in the battery and the temperature of the BBU. The BBU is designed to supply current to the cache memory for a minimum of 72 hours at 25°C ambient when fully charged.
8.2Maximum Memory Current
The BBU is designed with 4200mAh capacity batteries. The batteries are organized in 2 packs of 6 batteries, 1 pack per controller. Each pack includes a smart battery function, using a gas gauge device to control the battery critical information.
The maximum current that can be supplied for self refresh operations and still meet the 72 hour specification at end of battery life is 133mA per controller.
8.3Battery Pack Replacement Policy
The battery pack replacement policy is based on the available remaining capacity. The firmware will check the available capacity and send an alert to notify the administrator to change the battery pack if remaining capacity falls below 80% of the design capacity.
Under normal operation, a battery pack should last 2 to 3 years before it needs to be replaced.
8.4BBU Indicators
INSERT BBU
PICTURE
The back of the BBU has 2 sets of LEDs, one set for each battery pack.
INDICATOR | COLOUR | DESCRIPTION |
Charge/Full | Green/Yellow | Solid green when the battery pack is fully charged |
|
| Solid yellow when the battery pack is charging |
Replace | Red | Solid red when the battery pack needs replacing |
Raidtec FS3102 Hardware Installation Guide | Version 1.0 | 21 |