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VM66507: IMPROVE EDEVICE HEALTH CHECKING AND PATH SELECTION

A fix is available

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APAR status

  • Closed as new function.

Error description

  • Path control for EDEVICES enhancements include improved
    health checking, path selection, error reporting and statistics.
    Health checking of failing paths occur with more frequency
    to bring paths in recovery back online more regularly.
    The category of error and failure types is now recorded and
    made available using a new QUERY EDEVICE operand and updated
    monitor records. Asymmetric Logical Unit Access (ALUA) support
    within the path control module improves path selection for
    supported devices.
    

Local fix

  • N/A
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All SCSI EDEV users                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    ****************************************************************
    * RECOMMENDATION: APPLY PTF                                    *
    ****************************************************************
    The reliability of EDEVICE path control needs improvement.
    

Problem conclusion

Temporary fix

Comments

  • EDEV Path Management is an update to the path control module of
    the z/VM SCSI driver for emulated devices that heavily refactors
    the component and upgrades key functions in several areas:
    
    o   Path selection
    
    o   Path state tracking
    
    o   Path health checking
    
    Additional states have been added to the state tracking system
    for paths and devices, making it more robust, and the module
    will now be able to perform smarter path selection for disks
    that support dynamic ALUA by taking advantage of their
    optimized/non-optimized port group assignments.
    
    Many structures are enhanced or modified to store new status
    information, and those useful for diagnostics are exposed with
    modifications to the Query EDEV command and monitor records.
    
    To support APAR VM66507, a new edition of the following
    publication is available:
        SC24-6268-09: CP Commands and Utilities Reference
    

APAR Information

  • APAR number

    VM66507

  • Reported component name

    VM CP

  • Reported component ID

    568411202

  • Reported release

    720

  • Status

    CLOSED UR1

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2021-03-16

  • Closed date

    2021-08-30

  • Last modified date

    2022-03-28

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

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

    UM35902

Modules/Macros

  • CBITABLE CPLOAD   CPSYNTAX EDEVICE  EDEVSB   HCPCBI   HCPCKS
    HCPCRR   HCPDGB   HCPDMP   HCPDVT   HCPEDEV  HCPEQI   HCPHCQ
    HCPHSE   HCPMDLAT HCPMES   HCPMESB  HCPMNO   HCPMOM   HCPMXI
    HCPMXRBK HCPPPI   HCPSCFBK HCPSDU   HCPSDV   HCPSNQ   HCPSZA
    HCPSZB   HCPSZC   HCPSZD   HCPSZE   HCPSZG   HCPSZJ   HCPSZK
    HCPSZL   HCPSZM   HCPSZN   HCPSZO   HCPSZP   HCPSZQ   HCPSZQBK
    HCPSZR   HCPSZT   HCPSZV   HCPSZW   HCPSZX   HCPSZY   HCPSZZ
    HCPXLCEL HCPXLCPL HCPZSR   HCWAIX   HCWAI1   HCWAI2   HCWAI3
    HCWAI4   HCWAI5   HCWAI6   HCWAI7   HCWAI8   HCWAI9   HCWA10
    HCWA11   HCWA12   HCWA13   HCWA14   HCWA15   HCWA16   HCWA17
    HCWA18   HCWA19   HCWA20   HCWA21   HCWA22   HCWA25   HCWA27
    HCWCSP   HCWCS1   HCWCS2   HCWCS3   HCWEFS   HCWEF1   HCWIOS
    HCWIO1   HCWIO2   HCWIO3   HCWMPI   HCWPAI   HCWPA1   HCWPA2
    HCWPA3   HCWPA4   HCWPA5   HCWPA6   HCWPA7   HCWPA8   HCWPER
    HCWPSI   HCWPS1   HCWPS2   HCWPS3   HCWSCS   HCWSC1   MRIODDEV
    MRIODSZI MRIODVON MRMTRDEV
    

Publications Referenced
SC24626808    

Fix information

  • Fixed component name

    VM CP

  • Fixed component ID

    568411202

Applicable component levels

  • R720 PSY UM35902

       UP21/08/31 P 2201

Fix is available

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[{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG27M"},"Platform":[{"code":"PF054","label":"z\/OS"}],"Version":"720","Line of Business":{"code":"LOB16","label":"Mainframe HW"}}]

Document Information

Modified date:
29 March 2022