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IV55724: POSSIBLE DISK I/O ERROR WHEN USING ASYNCHRONOUS STORAGE DEVICES APPLIES TO AIX 6100-09

A fix is available

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APAR status

  • Closed as program error.

Error description

  • This APAR addresses a possible disk I/O error.  This error
    may happen only when all of the following are true:
    - The disk is an "Asynchronous" access device that has
    optimized and non-optimized paths.
    - The disk is attached using 16GB FC or 10GB FCoE adapters
    - The disk is using the AIX default PCM
    - The disk is using the round_robin or shortest_queue path
    selection algorithm
    - Errors occur in the SAN that simultaneously affect all
    of the optimized paths to the disk.
    
    If I/O fails under these conditions, there will be
    an error report entry with label SC_DISK_ERR3 and
    the first line of the "SENSE DATA" will end with
    0200 0400 0000 0000.
    

Local fix

Problem summary

  • This APAR addresses a possible disk I/O error.  This error
    may happen only when all of the following are true:
    - The disk is an "Asynchronous" access device that has
    optimized and non-optimized paths.
    - The disk is attached using 16GB FC or 10GB FCoE adapters
    - The disk is using the AIX default PCM
    - The disk is using the round_robin or shortest_queue path
    selection algorithm
    - Errors occur in the SAN that simultaneously affect all
    of the optimized paths to the disk.
    
    If I/O fails under these conditions, there will be
    an error report entry with label SC_DISK_ERR3 and
    the first line of the "SENSE DATA" will end with
    0200 0400 0000 0000.
    

Problem conclusion

  • Modified the SCSI disk driver to be less aggressive failing
    I/O that has been switched between different paths too many
    times.  Modified the AIX default PCM to improve the handling
    of specific errors from the drivers for the new FC adapters.
    

Temporary fix

Comments

  • 6100-07 - use AIX APAR IV58338
    6100-08 - use AIX APAR IV57954
    6100-09 - use AIX APAR IV55724
    6100-09 - use AIX APAR IV55724
    6100-09 - use AIX APAR IV55724
    7100-01 - use AIX APAR IV57675
    7100-02 - use AIX APAR IV57039
    7100-03 - use AIX APAR IV55668
    7100-04 - use AIX APAR IV55731
    

APAR Information

  • APAR number

    IV55724

  • Reported component name

    AIX 610 STD EDI

  • Reported component ID

    5765G6200

  • Reported release

    610

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Submitted date

    2014-02-20

  • Closed date

    2014-02-20

  • Last modified date

    2016-05-10

  • APAR is sysrouted FROM one or more of the following:

    IV55668

  • 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 U866340

       UP14/05/21 I 1000



Document information

More support for: AIX Standard Edition

Software version: 610

Operating system(s): AIX

Reference #: IV55724

Modified date: 10 May 2016