SE9990 Battery Destage Mode should be set OFF until fixed microcode is released

Asset ID:	1-73-1000711.1
Update Date:	2010-08-31
Keywords:

Solution Type FAB (standard) Sure

Solution 1000711.1 : SE9990 Battery Destage Mode should be set OFF until fixed microcode is released

Related Items


Sun Storage 9990 System

Related Categories


GCS>Sun Microsystems>Sun FAB>Standard>Controlled Proactive

PreviouslyPublishedAs
200929

Product
Sun StorageTek 9990 System

Impact

SE9990 has a battery destage feature which, in the event of an unplanned power outage, powers cache and disk with the array's batteries for a period of time sufficient to allow all cache-resident data to be written to disk. It has been discovered that enabling battery destage mode will cause a significant performance degradation, because it substantially lowers the cache write pending rate that the array will tolerate. With battery destage enabled, a cache write pending rate of only a few percentage points will cause the array to implement I/O "flow control", in which I/O acknowledgement is delayed in order to slow down the rate at which data is written to cache from attached hosts.

Contributing Factors

Symptoms

Root Cause

Resolution

If battery destage mode has been enabled on an SE9990 running microcode below 50-04-06, switch to "memory backup" mode as follows:

From the SVP enter maintenance mode.
Select the Install button.
Select the Change Configuration button.
Select the System Option button.
Select the Memory Backup radio button.
Confirm and save the changes.

Hitachi has provided a fix for this issue in microcode 50-04-06. Battery destage mode may be used with microcode greater than or equal to 50-04-06.

Modification History
Date: 10-OCT-2005

Added final resolution to Corrective Action.

Previously Published As
100715
Internal Comments

None.

Related Information

URL: http://webhome.sfbay/sejsc/AL/USP_01_038893.htm

Internal Eng Business Unit Group
KE Authors

Internal Kasp FAB Legacy ID
100715, I1199-1 (FIN)

Internal Sun Alert & FAB Admin Info
Critical Category:
Significant Change Date:
Avoidance: Patch
Responsible Manager: null
Original Admin Info: null

Internal SA-FAB Eng Submission
SE9990 Battery Destage Mode Should be Set OFF Until Fixed Microcode is Released.

Product_uuid
15644879-f179-11d8-ab63-080020a9ed93|Sun StorageTek 9990 System

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