PI80447: Disable MMAP for static files by default on z/OS

APAR status

• Closed as program error.

Error description

• Change the default to disable the use of memory-mapping to
  avoid potential issues such as deadlocks and latch contentions.
  

Local fix

• Remove the comment in the httpd.conf so it reads
  EnableMMAP off
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  IBM HTTP Server users on z/OS               *
  ****************************************************************
  * PROBLEM DESCRIPTION: Possible deadlock and contention        *
  *                      issues with memory-mapping enabled.     *
  ****************************************************************
  * RECOMMENDATION:  Apply this fix if using IBM HTTP Server on  *
  *                  z/OS                                        *
  ****************************************************************
  MMAP for static files is being disabled by default on z/OS.
  It can be re-enabled with "EnableMMAP ON"
  

Problem conclusion

• The default for memory-mapping directive was changed to
  disabled.
  
  This fix is targeted for IBM HTTP Server fix packs:
  - 7.0.0.45
  - 8.0.0.14
  - 8.5.5.12
  - 9.0.0.4
  

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:

Fix information

• Fixed component name

  WAS IHS ZOS

• Fixed component ID

  5655I3510

Applicable component levels