Mylex AcceleRAID 352, Installation Manual

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BBM-Battery Backup Module
Manual No. 775051 A-3
Maintenance
No maintenance is required. It is recommended that the BBM charge level be
periodically checked using the Gas Gauge function in GAM (see the Global
Array Manager Client Software Installation Guide and User Manual ).
Removing the
BBM
The BBM only needs to be removed if the Lithium-Ion battery no longer
accepts a charge properly (Lithium-Ion battery life expectancy is
approximately 1-1/2 years), or if the BBM is being salvaged from a
controller that has failed.
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WARNING
For battery service, please contact Mylex or
your authorized dealer for repairs. Batteries
are not user serviceable or replaceable.
BBM
Functional Description
Whenever the system is running, the BBM’s battery backup circuitry is
standing by, monitoring the voltage level supply of 3.3 V. In the event of a
power failure, the supply voltage level will begin to drop. When the battery
backup circuitry detects this voltage drop, it checks the status of the disk
cache. If the cache is empty, the battery backup circuitry does nothing.
If the cache contains data during a power failure, the BBM’s battery backup
circuitry will maintain cache data integrity until the power is restored. When
power is restored and the system finishes the bootstrap process, the cache
contents will be written to the disk array, also known as FLUSH.