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VM66673: MITIGATE EFFECTS OF GUEST MEMORY RESET TIME ON LOGOFF

A fix is available

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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 number

    VM66673

  • Reported component name

    VM CP CP

  • Reported component ID

    568411202

  • Reported release

    730

  • Status

    CLOSED UR1

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    YesSpecatt / New Function / Xsystem

  • Submitted date

    2023-03-06

  • Closed date

    2023-08-22

  • Last modified date

    2024-04-04

  • 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
    

Publications Referenced
SC24626873    

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

  • 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.

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Document Information

Modified date:
04 April 2024