ServeRAID M5014, M5015, an M5025 with iBBU08 and 12.13.0-0153 level of firmware not switching to Write-Back mode after BBU learn completion - IBM System x
RETAIN tip: H211101
On a ServeRAID M5014, M5015, or M5025 SAS/SATA Controller with an iBBU08 attached, after a relearn has completed, the virtual drives unexpectedly remain in Write-Through mode, causing reduced disk access performance.
(where iBBU = Intelligent Battery Backup Unit)
MegaRAID Storage Manager reports that the battery has degraded, and MegaCLI reports Remaining Capacity as being Low.
Only firmware level 12.13.0-0153 is affected with the iBBU08. iBBU07 is not affected.
Users can determine which battery is attached (iBBU07, or the newer iBBU08) by looking under the Physical tab in MegaRAID Storage Manager, and selecting the BBU.
Note: A battery type of 'iBBU' in this output indicates iBBU07. A battery type of 'iBBU08' indicates iBBU08.
MegaCLI can also be run with the following command:
The system can be any of the following IBM servers:
The system is configured with one or more of the following IBM options:
This tip is not software specific.
The 12.13.0-0153 level of firmware for the ServeRAID M5000 Series SAS/SATA Controller is affected.
The system has the symptom described above.
This behavior was corrected in firmware version 12.13.0-0179-1 of the ServeRAID M5000 Series SAS/SAS Controller firmware.
The file is available by selecting the appropriate Product Group, type of System, Product name, Product machine type, and Operating system on IBM Support's Fix Central web page, at the following URL:
Upgrade to the latest available firmware on IBM Fix Central.
Firmware version 12.13.0-0153 introduced a feature called Limited Band Charging (LBC) for the iBBU08. LBC is described in RETAIN Tip H21631 (MIGR-5093515).
The addition of Limited Band Charging introduced this issue. The root cause is that the threshold for marking a battery degraded is not taking LBC into account. Therefore, batteries were being prematurely marked as bad.
Applicable countries and regions
Document id: MIGR-5093954