Thermal Issues, Current Cache Policy Writethrough Battery Issues on Exadata

Asset ID:	1-72-1300423.1
Update Date:	2011-07-18
Keywords:

Solution Type Problem Resolution Sure

Solution 1300423.1 : Thermal Issues, Current Cache Policy Writethrough Battery Issues on Exadata

Applies to:

Exadata Database Machine X2-2 Qtr Rack - Version: Not Applicable and later [Release: N/A and later ]
Information in this document applies to any platform.

Symptoms

In /var/log/messages you see:

Jan 21 14:45:41 exapdb01 kernel: CPU8: Temperature above threshold, cpu clock throttled
Jan 21 14:45:41 exapdb01 kernel: CPU0: Temperature above threshold, cpu clock throttled
Jan 21 14:45:41 exapdb01 kernel: CPU11: Temperature/speed normal

Or

From /opt/MegaRAID/MegaCli/MegaCli64 -LDInfo -Lall -a0

Adapter 0 -- Virtual Drive Information:
Virtual Disk: 0 (Target Id: 0)
Name:
RAID Level: Primary-5, Secondary-0, RAID Level Qualifier-3
Size:271.945 GB
State: Optimal
Stripe Size: 1.0 MB
Number Of Drives:3
Span Depth:1
Default Cache Policy: WriteBack, ReadAheadNone, Direct, No Write Cache if Bad BBU
Current Cache Policy: WriteThrough, ReadAheadNone, Direct, No Write Cache if Bad BBU
Access Policy: Read/Write
Disk Cache Policy: Disabled
Encryption Type: None
Number of Dedicated Hot Spares: 1
0 : EnclId - 252 SlotId - 3

Exit Code: 0x00

Cause

The flash card show a cache policy of writethrough because the battery status is bad because the battery has exceeded the maximum temperature and stops charging.

Related to Sun unpublished BUG 6974465 - Exadata DB reports temperature threshold messages

Solution

Run the following command:

/opt/oracle.SupportTools/ipmitool sunoem cli "set /SP/policy FLASH_ACCELERATOR_CARD_INSTALLED=enabled"

This will change it from the current settings
/SP/policy
Properties:
COOLING_DOOR_INSTALLED = disabled
FLASH_ACCELERATOR_CARD_INSTALLED = disabled
HOST_AUTO_POWER_ON = disabled
HOST_LAST_POWER_STATE = enabled

show /SP/policy will display the change.

In the case of a battery or cache policy problem:

Run

/opt/MegaRAID/MegaCli/MegaCli64 -AdpBbuCmd -GetBbuStatus -a0

Check the battery is present and charging.
You may have to wait for an hour or so for the battery to start charging and the write through policy to change.

Re-run

/opt/MegaRAID/MegaCli/MegaCli64 -LDInfo -Lall -a0

Check that we now have:
Current Cache Policy: WriteBack

References

<BUG:6974465> - EXADATA DB REPORTS TEMPERATURE THRESHOLD MESSAGES
<NOTE:1329993.1> - LSI HBA disk cache policy is in WriteThrough mode in Exadata
<NOTE:1071220.1> - Oracle Sun Database Machine V2 Diagnosability and Troubleshooting Best Practices

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