OA66846: RECALL FAILURES FROM CLOUD ADR606E HTTP/1.1 404 NOT FOUND ARC1001I RC69 REAS0607 ARC1169I

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Recall failures from cloud ADR606E HTTP/1.1 404 Not Found.
  During migration of many similarly named data sets HSM may
  generate a MCA record with the same key for 2 different data
  data sets. If there is a failure during migration for the
  first data set it is possible during cleanup HSM may delete the
  second data set erroneously even though it migrated
  successfully causing the recall failure.
  

Local fix

• Many similarly named datasets that are migrated across multiple
  tasks and multiple instances of DFSMShsm can cause this issue.
  There is a patch where the generated Tssmmhh is replaced
  with Tcccchh, where cccc is the time in hundredths of seconds
  from the beginning of the hour, converted to four alphabetic
  characters, and hh is the hour.
  The documentation for this patch is included below.
  Please apply this patch to all systems via the ARCCMDxx member.
  A Stop and Start of HSM will be required. This Patch command
  can be issued to HSM dynamically also.
  .
  Changing DFSMShsm backup and migration generated data set names
  to reduce contention for similar names and eliminating a
  possible performance degradation
  .
  http://ibmurl.hursley.ibm.com/PV5W
  .
  To locate the other datasets that may have also run into this
  issue, we are recommending running:
  AUDIT DATASETCONTROLS(MIGRATION) NOFIX ODS(output.dsn)
  This will identify the datasets that will need to be recovered
  from a backup.  You can recover the datasets and then remove the
  obsolete records via the AUDIT using the FIX instead of NOFIX or
  these can be done manually.   Please provide us with the output
  dataset so we can review prior to recovery.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All z/OS v2r5 and higher users of DFSMShsm.  *
  ****************************************************************
  * PROBLEM DESCRIPTION: DFSMShsm will generate names for        *
  *                      migration data sets. Sometimes these    *
  *                      names may collide, causing performance  *
  *                      issues, and sometimes a race condition  *
  *                      may occur during name generation that   *
  *                      has the potential for destructive       *
  *                      data actions.                           *
  ****************************************************************
  DFSMShsm may experience a race condition around generated
  migration names. Such a race condition can occur when an
  attempt to migrate a data set to the cloud fails, and during
  cleanup, a subsequent migration for another data set occurs.
  The second migration generates the same data set name as the
  first, and since the first data set is actively being
  cleaned up (from the failed migration) it inadvertently
  cleans up the second migrated data set also. This results
  in a data loss scenario of the second data set.
  
  KEYWORDS: DFSMSCS/K
  

Problem conclusion

• DFSMShsm has been modified to correct the problem.
  

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:

  UJ95981 UJ95982

Modules/Macros

• ARCMCSQC ARCMDSUV ARCMVDS
  

Fix information

• Fixed component name

  DFSMSHSM, ISMF

• Fixed component ID

  5695DF170

Applicable component levels

• R250 PSY UJ95982

     UP24/10/01 P F409 ¢

• R310 PSY UJ95981

     UP24/10/01 P F409 ¢

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.