A fix is available
APAR status
Closed as program error.
Error description
When using the round robin MPIO algorithm, the SCSI disk head driver may send out extraneous Clear ACA task management commands. Most storage devices just accept and ignore such extra commands. But if a storage device rejects the extra clear ACA (as it is allowed to do per the standards), this could result in extra LUN or Target reset commands, which could affect I/O throughput.
Local fix
Problem summary
When using the round robin MPIO algorithm, the SCSI disk head driver may send out extraneous Clear ACA task management commands. Most storage devices just accept and ignore such extra commands. But if a storage device rejects the extra clear ACA (as it is allowed to do per the standards), this could result in extra LUN or Target reset commands, which could affect I/O throughput.
Problem conclusion
Modified the SCSI disk head driver to close a timing window that caused the head driver to send multiple Clear ACA task management functions for a single check condition.
Temporary fix
Comments
5300-10 - use AIX APAR IZ91233 5300-11 - use AIX APAR IZ91151 5300-12 - use AIX APAR IZ90693 6100-03 - use AIX APAR IZ93673 6100-04 - use AIX APAR IZ93601 6100-05 - use AIX APAR IZ93420 6100-06 - use AIX APAR IZ93005 6100-06 - use AIX APAR IZ85136 7100-00 - use AIX APAR IZ85504
APAR Information
APAR number
IZ93673
Reported component name
AIX 610 STD EDI
Reported component ID
5765G6200
Reported release
610
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Submitted date
2011-01-28
Closed date
2011-01-28
Last modified date
2013-04-16
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
AIX 610 STD EDI
Fixed component ID
5765G6200
Applicable component levels
R610 PSY U839086
UP11/03/22 I 1000
PTF to Fileset Mapping
U839086 devices.fcp.disk.rte 6.1.3.6
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Document Information
Modified date:
16 April 2013