VM66673: MITIGATE EFFECTS OF GUEST MEMORY RESET TIME ON LOGOFF

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• Guests with large amounts of memory instantiated can experience
  long delays during LOGOFF because of the sheer number of pages
  that need to be reclaimed from memory and disk.  This change
  allows guest memory reset to proceed asynchronously, reducing
  the interval between initation of a guest's LOGOFF and its
  subsequent ability to re-LOGON and providing indications when
  guest memory is still being reclaimed.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users running guests with large amounts  *
  *                 of instantiated memory (hundreds of          *
  *                 gigabytes) that need to be logged off and    *
  *                 back on.                                     *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  ****************************************************************
  * RECOMMENDATION: APPLY PTF                                    *
  ****************************************************************
  Guests with large amounts of memory instantiated can experience
  long LOGOFF times because of the sheer number of pages that need
  to be reclaimed from memory and disk.
  

Problem conclusion

Temporary fix

• FOR RELEASE VM/ESA CP/ESA R730 :
  PREREQ: NONE
  CO-REQ: NONE
  IF-REQ: NONE
  

Comments

• Code has been changed so that when the LOGOFF process begins to
  release guest memory, the user becomes unknown to most of CP and
  can be logged on again as a new instance while the release of
  memory continues. For a guest with a large amount of memory
  instantiated, the release process can take a considerable
  amount of time. Accordingly, unless there are sufficient
  additional resources available, it is advisable to avoid
  restarting a workload on the new instance that consumes
  substantial memory and instead to perform maintenance or
  other activities that occasioned the LOGOFF.
  
  Several commands now identify a guest that is in the memory
  release phase of LOGOFF. For all these command responses,
  alphabetic characters in the guest user identifier will have
  been translated to lower case. QUERY NAMES will show the guest
  as LOF; LOCATE VMDBK with an operand that matches the lower
  case guest user ID will show the VMDBK type as LOGOFF; and
  INDICATE PAGING will show LOGOFF in a new STATUS column for
  the guest.
  

APAR Information

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

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

  UM90339

Modules/Macros

• HCPCQU   HCPESS   HCPIIO   HCPLUS   HCPRST   HCPSWI   HCPTHK
  HCPUSO   HCPUSP   LOGOFF   MONITOR  NAMES    PAGING   VMDBK
  

Fix information

• Fixed component name

  VM CP CP

• Fixed component ID

  568411202

Applicable component levels

• R730 PSY UM90339

     UP23/08/28 P 2401  

Fix is available

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