User's Manual

RAID Controller Batteries 187
The battery learn cycle discharges and then fully charges the controller
battery.
The Learn cycle recalibrates the battery integrated circuit so that the
controller can determine whether the battery can maintain the controller
cache for the prescribed period of time in the event of a power loss. For
example, some controller batteries are required to maintain the controller
cache for 72 hours.
While the Learn cycle is in progress, the battery may not be able to maintain
the cache during a power loss. If the controller is using write-back cache
policy, then the controller changes to write-through cache policy until the
Learn cycle completes. The write-through cache policy writes the data
directly to the disk and reduces the risk that data can be lost in the cache if
there is a power loss.
NOTE: If you have set the controller to write-back force cache policy, then the
cache policy is not changed during the Learn cycle. When using write-back force
cache policy, it is possible for data loss to occur if there is a power loss while the
Learn cycle is in progress.
The controller firmware automatically initiates the Learn cycle every 90 days.
You can, however, delay the start time of the Learn cycle for a further seven
days, after which the firmware automatically initiates the Learn cycle. For
more information, see Battery Delay Learn Cycle.
NOTE: The Learn cycle cannot be performed while the battery is charging. If either
a user or the controller firmware initiate the Learn cycle while the battery is
charging, then the battery Learn State displays Requested. When the battery is fully
charged, the Learn cycle begins.
NOTE: The battery learn cycle is initiated automatically for the PERC H710, PERC
H710P, PERC H810, and PERC H310 controllers, irrespective of the learn cycle
duration.
Battery Delay Learn Cycle
Does my controller support this feature? See Supported Features.
The controller firmware automatically initiates the battery learn cycle every
90 days. Although you cannot stop the firmware from running the Learn
cycle, you can delay the start time of the learn cycle for up to seven days. For
more information on the battery learn cycle, see Start Learn Cycle.