VM66507: IMPROVE EDEVICE HEALTH CHECKING AND PATH SELECTION

Obtain the fix for this APAR.

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

• FOR RELEASE VM/ESA CP/ESA R720 :
  PREREQ: VM66439 VM66477 VM66173 VM66420 VM66504 VM66449
  PREREQ: VM66485
  PREREQ: VM66469 VM66510 VM66471 VM66212 VM66271 VM66414
  PREREQ: VM66545
  CO-REQ: NONE
  IF-REQ: NONE
  

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 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
  

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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