VM66578: VARY ON FAILS FOR 1024TH EDEV

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Unable to VARY ON more than 1023 EDEVs. HCPSZV8701I and
  HCPCPN8700I are received setting online a 1024th EDEV.
  
  Complete message information follows:
  HCPSZV8701I Path FCP DEV <rdev> WWPN <wwpn> LUN <lun> was
  deleted from EDEV nnnn because an unexpected failure occurred
  during vary on.  A SCSI I/O operation performed on this path
  has failed. Support Code = 000C
  
  HCPCPN8700I Emulated Device nnnn cannot be varied online because
  there are no valid paths defined to the device.
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of z/VM EDEVICEs                   *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  ****************************************************************
  * RECOMMENDATION: APPLY PTF                                    *
  ****************************************************************
  When there are already 1023 EDEVICEs online, each with unique
  LUNs that have paths defined on the same target WWPN, issuing
  VARY ON for a 1024th EDEVICE using a 1024th LUN that has paths
  defined to the same target WWPN as the previous EDEVICEs will
  cause the paths to be deleted, and the VARY ON to fail.
  
  This occurs due to a limit of unique LUN tags available per
  target. During VARY ON, each LUN is given a unique tag, with a
  limit of 1023 unique LUN tags per target. Attempting to use a
  1024th LUN to define a path on a target WWPN, when 1023 LUNs
  already have paths defined to it, will result in an error, as
  there are no more tags left to be assigned for that target WWPN.
  This causes the path to be deleted, and the VARY ON for that
  EDEVICE will fail if there are no other valid paths defined to
  different target WWPN that has not exceeded it unique LUN limit.
  

Problem conclusion

• The limit of unique LUN tags was increased to allow a maximum
  of 4095 EDEVICEs to be brought online for each target WWPN.
  

Temporary fix

Comments

APAR Information

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

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

  UM35916

Modules/Macros

• HCPSZB   HCPSZG   HCPSZN   HCPSZQ   HCPSZY   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   HCWEFS   HCWEF1   HCWMPI   HCWPSI   HCWPS1
  HCWPS2   HCWPS3   HCWSCS   HCWSC1
  

Fix information

• Fixed component name

  VM CP CP

• Fixed component ID

  568411202

Applicable component levels

• R720 PSY UM35916

     UP21/12/02 I 1000

Fix is available

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