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PI14413: SERVER HEALTH NOT UPDATED FROM ZERO. 14/09/02 PTF PECHANGE

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APAR status

  • Closed as program error.

Error description

  • WAS 7.0.0.31 introduced the use of WLM Health API (IWM4HLTH)
    that allows a server to indicate it's 'health' to WLM. However,
    the health is never incremented from the initial value of 0.
    One message is seen in the logs:
    BBOO0411I SERVER WLM HEALTH PERCENTAGE IS NOW 0
    
    But no further increments are made and no further messages
    BBOO0411I are issued. Hence the server (part of a cluster) never
    receives any work from the Sysplex Distributor.
    A netstat cmd:
    netstat -O DETAIL -p XXXXXXX -P YYYYYY
    will show "Health: 000" and "TotalConn 0"
    

Local fix

  • There is no workaround that allows you to continue to use the
    SERVERWLM routing algorithm as your DISTMethod.  But, to ensure
    all servers continue to receive work without interruption you
    may perform one or both of the following actions:
    
    (1)  Change the "DISTMethod" on the "VIPADISTRIBUTE" definition
    to "BASEWLM".  A DISTMethod of BASEWLM ignores the WLM health
    information and instead uses generic LPAR information to route
    requests.
    
    (2)  Upgrade all nodes to 7.0.0.31.  The root of this problem is
    not the specific health value given by WLM, but the RELATIVE
    health value.  At the 7.0.0.29 level, the health value from WLM
    was 100% for all servers at all times.  At the 7.0.0.31 level,
    the health value from WLM is 0% for all servers at all times.
    It is this mismatch that causes work to get routed only to the
    7.0.0.29 servers when the nodes are mixed-level.
    If all nodes are at 7.0.0.31, then the relative health values of
    0% essentially cancel themselves out and things work the same
    as if both relative health values were 100%.
    
    Note that these two workarounds can be combined by using a
    DISTMethod of BASEWLM during the upgrade of the nodes to
    7.0.0.31, and once all nodes are upgraded the DISTMethod can be
    set back to SERVERWLM.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server V7.0                                 *
    ****************************************************************
    * PROBLEM DESCRIPTION: WebSphere Application Server for z/OS   *
    *                      Controller receives the initial         *
    *                      BBOO0411I message but no additional     *
    *                      instances.                              *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    The WLM Health API (IWM4HLTH) is called early in the
    initialization of the Controller with a value of zero.
    BBOO0411I SERVER WLM HEALTH PERCENTAGE IS NOW 0
    Subsequent calls should be initiated from a Controller routine
    that gets control to start the deferred set of communication
    listeners.  This call is missing.
    

Problem conclusion

  • Code has been modified to include the omitted call to initiate
    calls to the WLM Health API.  This will cause a growth in the
    servers WLM Health value until it reaches a value of 100.
    
    APAR PI14413 is currently targeted for inclusion in Fix Pack
    7.0.0.33 of WebSphere Application Server.
    
    Please refer to URL:
    //www.ibm.com/support/docview.wss?rs=404&uid=swg27006970
    for Fix Pack availability.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PI14413

  • Reported component name

    WEBSPHERE FOR Z

  • Reported component ID

    5655I3500

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    YesPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2014-03-25

  • Closed date

    2014-05-13

  • Last modified date

    2014-09-02

  • 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

    WEBSPHERE FOR Z

  • Fixed component ID

    5655I3500

Applicable component levels

  • R700 PSY UI18561

       UP14/06/21 P F406

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.



Document information

More support for: WebSphere Application Server for z/OS
General

Software version: 7.0

Reference #: PI14413

Modified date: 02 September 2014