Perc6 policy writeback and bbu

Nicolas Chipaux chipaux at
Thu Jul 29 11:42:20 CDT 2010


We notice that the Perc card one of our filer has switched to WriteThrough
policy without any particular reason. We try to switch back to WriteBack to use
the BBU, but the controler will not allow us to do that. We had to force the
config to CachedBadBBU  to get the policy back to WriteBack but this situation
is highly unstable. In the BBU information available with MegaCLI nothing seems
to indicate any problem on the battery. 

Any idea ?

So :

Default Cache Policy: WriteBack, ReadAheadNone, Cached, No Write Cache if Bad BBU
Current Cache Policy: WriteThrough, ReadAheadNone, Cached, No Write Cache if Bad BBU

=> MegaCli -LDSetProp WB -LAll -a0 
Set Write Policy to WriteBack on Adapter 0, VD 0 (target id: 0) success
Exit Code: 0x00

no success.

=> MegaCli -LDSetProp CachedBadBBU -LAll -a0 
Then the policy is switch to WriteBack ignoring the BBU status

In the BBU status from MegaCLI, where is the battery flagged as 'bad' ?

If we start a short learn cycle on the battery unit, the current policy first
switches a few minutes to "WriteBack" (?!) but when the power level is going
under the default threshold, the policy switch back to WriteThrough which is a
normal behavior. But when the power level is back up wll above the threshold,
the policy is still WriteThrough

About the battery unit :

=> MegaCli -AdpBbuCmd -a0
BBU status for Adapter: 0

BatteryType: BBU
Voltage: 4040 mV
Current: 0 mA
Temperature: 32 C
Firmware Status: 00000000

Battery state: 

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

Relative State of Charge: 98 %
Charger Status: Complete
Remaining Capacity: 835 mAh
Full Charge Capacity: 854 mAh
isSOHGood: Yes

BBU Capacity Info for Adapter: 0

Relative State of Charge: 98 %
Absolute State of charge: 49 %
Remaining Capacity: 835 mAh
Full Charge Capacity: 854 mAh
Run time to empty: 65535 Min
Average time to empty: 65535 Min
Average Time to full: 65535 Min
Cycle Count: 11
Max Error: 0 %
Remaining Capacity Alarm: 170 mAh
Remaining Time Alarm: 10 Min

BBU Design Info for Adapter: 0

Date of Manufacture: 10/13, 2008
Design Capacity: 1700 mAh
Design Voltage: 3700 mV
Specification Info: 33
Serial Number: 368
Pack Stat Configuration: 0x0008
Manufacture Name: SANYO
Device Name: DLKR174
Device Chemistry: LION
Battery FRU: N/A

BBU Properties for Adapter: 0

Auto Learn Period: 7776000 Sec
Next Learn time: 341873114 Sec 
Learn Delay Interval:0 Hours
Auto-Learn Mode: Enabled

Information about the Perc6 :

Product Name    : PERC 6/E Adapter
Serial No       : 1122334455667788
FW Package Build: 6.1.1-0047

                    Mfg. Data
Mfg. Date       : 06/24/08
Rework Date     : 06/24/08
Revision No     : 
Battery FRU     : N/A

                Image Versions In Flash:
FW Version         : 1.21.02-0528
BIOS Version       : 2.01.00
WebBIOS Version    : 1.1-46-e_15-Rel
Ctrl-R Version     : 1.02-014B
Preboot CLI Version: 01.00-020:#%00004
Boot Block Version :


Nicolas Chipaux

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