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Disk alert: current capacity of the battery is below threshold


Article ID: 213975


Updated On:


Security Analytics


Security Analytics uses a generic message to alert on hardware issues.  In this case, even though the error was a disk alert, the underlying problem is the battery capacity is below the predetermined threshold.  The error message in /var/log/messages may look like this:

Adapter 0; seqNum: 0x00046a52; Time: Mon Apr 26 23:16:57 2021; Event Description: Current capacity of the battery is below threshold; 


The battery on the RAID controller is there for redundancy.  It is not required for normal performance, but it does help if there are any power outages to prevent corruption.


Any LSI RAID controller, which are included in both Dell and Symantec S500 series appliances


Battery Health can be determined by running the following command from a command prompt:

megacli -adpbbucmd -getbbustatus -aX  (where X is the Adapter specified in the warning message)

A normal, healthy battery will look like this:

[root#server ~]#  megacli -adpbbucmd -getbbustatus -a0
BBU status for Adapter: 0

BatteryType: BBU
Voltage: 3932 mV
Current: 0 mA
Temperature: 39 C

BBU Firmware Status:

  Charging Status              : None
  Voltage                      : OK
  Temperature                  : OK
  Learn Cycle Requested        : No
  Learn Cycle Active           : No
  Learn Cycle Status           : OK
  Learn Cycle Timeout          : No
  I2c Errors Detected          : No
  Battery Pack Missing         : No
  Battery Replacement required : No
  Remaining Capacity Low       : No
  Periodic Learn Required      : No
  Transparent Learn            : No

Battery state: 

  Fully Discharged        : No
  Fully Charged           : Yes
  Discharging             : No
  Initialized             : No
  Remaining Time Alarm    : No
  Remaining Capacity Alarm: Yes
  Discharge Terminated    : No
  Over Temperature        : No
  Charging Terminated     : No
  Over Charged            : No

Relative State of Charge: 99 %
Charger Status: Complete
Remaining Capacity: 488 mAh
Full Charge Capacity: 493 mAh
isSOHGood: Yes

Exit Code: 0x00

"Relative State of Charge" should be in the upper 80s or 90s.

If battery charge is low, you can try to perform a battery learn cycle, which discharges the battery and attempt to recharge it.  NOTE:  In Dell PERC RAID controllers, virtual disks automatically switch to Write-Through mode when the battery charge is low.  Once the battery charge is sufficient, Write-Back mode will be re-enabled.

The time frame for a completion of a learn cycle is a function of the battery charge capacity and the discharge/charge currents used.  The expected time frame for a completion of a learn cycle is approximately seven hours and consists of the following parts:

  • Learn cycle discharge cycle:  approximately three hours
  • Learn cycle charge cycle:  approximately four hours

To force a learn cycle, run the following command:   megacli -adpbbucmd -bbulearn -aX  (where X is the Adapter number).  Please wait for several days for the battery to normalize and then check for any new errors.

If the battery is still showing a low charge after the learn cycle is completed, contact technical support to get the battery replaced.