Array performance degradation as a result of the cache changing to write-through.

Asset ID:	1-73-1000682.1
Update Date:	2010-08-26
Keywords:

Solution Type FAB (standard) Sure

Solution 1000682.1 : Array performance degradation as a result of the cache changing to write-through.

Related Items


Sun Storage 3510 FC Array
 Sun Storage 3310 Array
 Sun Storage 3511 SATA Array
 Sun Storage 3320 SCSI Array

Related Categories


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

PreviouslyPublishedAs
200894

Product
Sun StorageTek 3310 SCSI Array
Sun StorageTek 3510 FC Array
Sun StorageTek 3320 SCSI Array
Sun StorageTek 3511 SATA Array

Bug Id
<SUNBUG: 6327514>, <SUNBUG: 6256792>

Impact

Firmware 4.1x introduced a new functionality to decide when the cache changes to write-through. This is the auto-write-through-trigger. One of the triggers is battery-backup-failure which, when enabled, will change the cache to write-though should a battery fail.

However, this trigger does not distinguish between a battery failure and a re-charge cycle. As a result, performance of the array degrades to add to the performance hit already caused by the 4.1x firmware.

Symptoms

Battery re-charging messages indicating the re-charging cycle, followed by the cache changing to write-through. Consequently a drop in i/o performance.

<Tue Jan 24 02:06:43 2006> Controller BBU is Charging !

<Tue Jan 24 02:06:44 2006> Force Controller Write-Through on Trigger Cause

<Tue Jan 24 05:55:12 2006> NOTICE: Controller BBU Fully Charged !

<Tue Jan 24 05:55:12 2006> Controller Default Write Policy Restore

Root Cause

The controller firmware 4.1x is unable to distinguish between a battery failure and a battery re-charging event.

Workaround

Patch Information per Array:

Patch 113723-15 is for SE3510 FC Array
Patch 113724-09 is for SE3511 SATA Array
Patch 113722-15 is for SE3310 SCSI Array
Patch 113730-01 is for SE3320 SCSI Array

Resolution

Previously Published As
102222
Internal Comments

Internal Contributor/submitter
[email protected]

Internal Eng Business Unit Group
KE Authors

Internal Eng Responsible Engineer
[email protected]

Internal Services Knowledge Engineer
[email protected]

Internal Escalation ID
1-12760796

Internal Resolution Patches
113723-15, 113724-09, 113722-15, 113730-01

Internal Kasp FAB Legacy ID
102222

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

Internal SA-FAB Eng Submission
Bug 6327514 causes array performance degradation as a result of the cache changing to write-through.

Product_uuid
3db30178-43d7-4d85-8bbe-551c33040f0d|Sun StorageTek 3310 SCSI Array
58553d0e-11f4-11d7-9b05-ad24fcfd42fa|Sun StorageTek 3510 FC Array
95288bce-56d3-11d8-9e3a-080020a9ed93|Sun StorageTek 3320 SCSI Array
9fdbb196-73a6-11d8-9e3a-080020a9ed93|Sun StorageTek 3511 SATA Array

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