OA04699: WLM SUPPORT FOR STATEFUL SESSION PLACEMENT

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• New Function
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of z/OS 1.4                        *
  *                 (HBB7707) and above.                         *
  ****************************************************************
  * PROBLEM DESCRIPTION: Due to HTTP Session affinity, it is not *
  *                      possible for WLM to properly scale the  *
  *                      WEB Container and the EJB Container     *
  *                      when an entire application (JSPs,       *
  *                      servlets, EJBs) is deployed as one EAR  *
  *                      in the same WAS Control Region. User    *
  *                      sessions are established and an         *
  *                      affinity is established to one WAS      *
  *                      server region. Once user transactions   *
  *                      volume grows, a single WAS server       *
  *                      region cannot handle the volume and WLM *
  *                      cannot move incoming transactions due   *
  *                      to the affinity to the JVM.  To address *
  *                      this problem, customers must set up and *
  *                      manage this environment much like a     *
  *                      WebSphere Distributed solution by       *
  *                      creating more control regions and load  *
  *                      balancing outside of WLM.               *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  WLM wakes up suspended server task when new work requests are
  inserted by a queue manager. The wake up mechanism tries to keep
  the first bound server address space highly utilized and tries
  to decrease the work utilization so that some server address
  spaces potentially have idle servers. This is beneficial when
  SRM decides to stop server address spaces. It is counter
  productive when the application inserts too many work elements
  which create an object affinity to a server region. In this case
  it is better to spread the work across all server regions.
  

Problem conclusion

Temporary fix

Comments

• A new wake up mechanism ROUND_ROBIN for suspended server tasks
  was added in IWME2STR. It will take the number of already
  established work affinities and the number of currently active
  servers per address space into account when it tries to find a
  server region for new work requests.
  This increases the likelihood that work affinities are spread
  equally across started server regions.
  

APAR Information

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

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

  UA10757 UA10758 UA10818

Modules/Macros

• IRAEVREQ IRASRMST IWMAEDEF IWMAEDEP IWMCTKEY
  IWMDEFS  IWME2ASC IWME2BND IWME2CON IWME2DIS IWME2INF IWME2RAE
  IWME2REG IWME2RSR IWME2SEL IWME2SEM IWME2SRS IWME2STR IWME2TTM
  IWMQ2CON IWMQ2DAE IWMQ2DIS IWMQ2INS IWMQ2SEL IWMQ2VEQ
  

Publications Referenced

SA22761904

SA22761905

SA22761906

Fix information

• Fixed component name

  WORK LOAD MANAG

• Fixed component ID

  5752SCWLM

Applicable component levels

• R707 PSY UA10757

     UP04/06/03 P F406

• R708 PSY UA10758

     UP04/06/03 P F406

• R717 PSY UA10818

     UP04/06/03 P F406

Fix is available

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Product categories:

Software

Operating System

z/OS family

APARs - z/OS environment

Operating system(s):

MVS, z/OS

Software version:

708

Reference #:

OA04699

IBM Group:

IBM Server Group

Modified date:

2004-08-27