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PM12112: CHANGE HOW PLUG-IN FINDS ANOTHER SERVER IF THE AFFINITY SERVER WAS ALREADY MARKED DOWN WHEN THE REQUEST ARRIVES.

Fixes are available

6.1.0.33: Java SDK 1.5 SR12 FP1 Cumulative Fix for WebSphere
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for AIX
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for HP-UX
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for IBM i
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for Linux
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for Solaris
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for Windows
7.0.0.13: Java SDK 1.6 SR8FP1 Cumulative Fix for WebSphere Application Server
6.1.0.35: Java SDK 1.5 SR12 FP2 Cumulative Fix for WebSphere
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for AIX
7.0.0.15: Java SDK 1.6 SR9 Cumulative Fix for WebSphere Application Server
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for HP-UX
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for IBM i
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Linux
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Solaris
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Windows
6.1.0.37: Java SDK 1.5 SR12 FP3 Cumulative Fix for WebSphere
7.0.0.17: WebSphere Application Server V7.0 Fix Pack 17
7.0.0.17: Java SDK 1.6 SR9 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.19: WebSphere Application Server V7.0 Fix Pack 19
7.0.0.21: WebSphere Application Server V7.0 Fix Pack 21
7.0.0.23: WebSphere Application Server V7.0 Fix Pack 23
7.0.0.25: WebSphere Application Server V7.0 Fix Pack 25
7.0.0.27: WebSphere Application Server V7.0 Fix Pack 27
7.0.0.29: WebSphere Application Server V7.0 Fix Pack 29
6.1.0.47: WebSphere Application Server V6.1 Fix Pack 47
7.0.0.31: WebSphere Application Server V7.0 Fix Pack 31
7.0.0.27: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.33: WebSphere Application Server V7.0 Fix Pack 33
7.0.0.35: WebSphere Application Server V7.0 Fix Pack 35
7.0.0.37: WebSphere Application Server V7.0 Fix Pack 37
7.0.0.39: WebSphere Application Server V7.0 Fix Pack 39
7.0.0.41: WebSphere Application Server V7.0 Fix Pack 41
7.0.0.43: WebSphere Application Server V7.0 Fix Pack 43
6.1.0.39: Java SDK 1.5 SR12 FP4 Cumulative Fix for WebSphere Application Server
6.1.0.41: Java SDK 1.5 SR12 FP5 Cumulative Fix for WebSphere Application Server
6.1.0.43: Java SDK 1.5 SR13 Cumulative Fix for WebSphere Application Server
6.1.0.45: Java SDK 1.5 SR14 Cumulative Fix for WebSphere Application Server
6.1.0.47: Java SDK 1.5 SR16 Cumulative Fix for WebSphere Application Server

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • In the Failover section of Information Center page "Web server
    plug-ins", it has the following description of plug-in failover
    behavior:
    If a request connection exceeds the time limit specified on the
    ConnectTimeout property in the plugin-cfg.xml file, or a 5xx
    error is returned from the application server, the Web server
    plug-in marks the server as down, and attempts to connect to the
    next application server in the list of primary servers that is
    specified for the PrimaryServers property in the plugin-cfg.xml
    file. If the Web server plug-in successfully connects to another
    application server, all requests that were pending for the down
    application server are sent to this other application server.
    All other new and affinity requests are sent to other servers,
    based on whether round robin or random is the setting for the
    Load balancing option Web server plug-in request routing
    property.
    http://publib.boulder.ibm.com/infocenter/wasinfo/v7r0/index.jsp?
    topic=/com.ibm.websphere.nd.doc/info/ae/ae/cwsv_plugins.html
    
    Suppose an affinity request arrives at plug-in after the
    affinity server had been marked down. Currently, plug-in will
    look for the next up application server in the primary server
    list; and route the affinity request to it. This behavior is not
    the same as described in the Information Center.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  IBM WebSphere Application Server web server *
    *                  plugin users                                *
    ****************************************************************
    * PROBLEM DESCRIPTION: Failed Affinity connections are not     *
    *                      distributed uniformly                   *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    When an affinity server is offline, the pending connections
    will be directed to the next server in the primaryserver list
    instead of distributed among the available servers. This can
    cause an overloading of the "next server" which can lead to a
    cascading failure situation.
    

Problem conclusion

  • The code has been modified to distribute the requests among the
    available servers.
    
    The fix for this APAR is currently targeted for inclusion in
    fix packs 6.1.0.33 and 7.0.0.13.  Please refer to the
    Recommended Updates page for delivery information:
    http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
    

Temporary fix

  • Set the maxconnections to limit the number of connections
    which will be sent to the "next server" to avoid an unloading
    situation.
    

Comments

APAR Information

  • APAR number

    PM12112

  • Reported component name

    WEBS APP SERV N

  • Reported component ID

    5724H8800

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-04-13

  • Closed date

    2010-04-27

  • Last modified date

    2010-10-15

  • 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

    WEBS APP SERV N

  • Fixed component ID

    5724H8800

Applicable component levels

  • R61A PSY

       UP

  • R61H PSY

       UP

  • R61I PSY

       UP

  • R61P PSY

       UP

  • R61S PSY

       UP

  • R61W PSY

       UP

  • R61Z PSY

       UP

  • R700 PSY

       UP



Document information

More support for: WebSphere Application Server
General

Software version: 7.0

Reference #: PM12112

Modified date: 15 October 2010


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