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PM59542: LOSING SESSION AFFINITY WHEN PLUGIN IS USING OVER 2048 FILE DESCRIPTORS

Fixes are available

8.0.0.4: WebSphere Application Server V8.0 Fix Pack 4
7.0.0.25: WebSphere Application Server V7.0 Fix Pack 25
8.5.0.1: WebSphere Application Server V8.5 Fix Pack 1
8.0.0.5: WebSphere Application Server V8.0 Fix Pack 5
7.0.0.27: WebSphere Application Server V7.0 Fix Pack 27
8.5.0.2: WebSphere Application Server V8.5 Fix Pack 2
8.0.0.6: WebSphere Application Server V8.0 Fix Pack 6
7.0.0.29: WebSphere Application Server V7.0 Fix Pack 29
8.0.0.7: WebSphere Application Server V8.0 Fix Pack 7
8.0.0.8: WebSphere Application Server V8.0 Fix Pack 8
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
8.0.0.9: WebSphere Application Server V8.0 Fix Pack 9
7.0.0.35: WebSphere Application Server V7.0 Fix Pack 35
8.0.0.10: WebSphere Application Server V8.0 Fix Pack 10
7.0.0.37: WebSphere Application Server V7.0 Fix Pack 37
8.0.0.11: WebSphere Application Server V8.0 Fix Pack 11
7.0.0.39: WebSphere Application Server V7.0 Fix Pack 39
8.0.0.12: WebSphere Application Server V8.0 Fix Pack 12
7.0.0.41: WebSphere Application Server V7.0 Fix Pack 41
8.0.0.13: WebSphere Application Server V8.0 Fix Pack 13
7.0.0.43: WebSphere Application Server V7.0 Fix Pack 43
8.0.0.14: WebSphere Application Server V8.0 Fix Pack 14
7.0.0.45: WebSphere Application Server V7.0 Fix Pack 45
8.0.0.15: WebSphere Application Server V8.0 Fix Pack 15
7.0.0.25: Java SDK 1.6 SR11 Cumulative Fix for WebSphere Application Server
7.0.0.27: Java SDK 1.6 SR12 Cumulative Fix for WebSphere Application Server
7.0.0.29: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.45: Java SDK 1.6 SR16 FP60 Cumulative Fix for WebSphere Application Server
7.0.0.31: Java SDK 1.6 SR15 Cumulative Fix for WebSphere Application Server
7.0.0.35: Java SDK 1.6 SR16 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.37: Java SDK 1.6 SR16 FP3 Cumulative Fix for WebSphere Application Server
7.0.0.39: Java SDK 1.6 SR16 FP7 Cumulative Fix for WebSphere Application Server
7.0.0.41: Java SDK 1.6 SR16 FP20 Cumulative Fix for WebSphere Application Server
7.0.0.43: Java SDK 1.6 SR16 FP41 Cumulative Fix for WebSphere Application Server
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APAR status

  • Closed as program error.

Error description

  • When the plugin connects to the backend server, if the file
    descriptor it uses is over 2048, the select fails.  This causes
    the plugin to believe the backend server is down and it routes
    the request to another backend server.  This causes loss of
    session affinitity.
    
    Plugin log shows
    ERROR: ws_common: websphereGetStream: Failed to connect; OS err
    = 121
    ERROR: ws_common: websphereExecute: Failed to create the stream
    ERROR: ws_server: serverSetFailoverStatus: Marking server down
    ERROR: ws_common: websphereHandleRequest: Failed to execute the
    transaction to 'server'on host 'host'; will try another one
    
    You can verify if this is the issue by issuing D
    OMVS,L,PID=http_server_pid and look at MAXFILEPROC.  If the high
    water usage is over 2048 - this issue can occur.
    

Local fix

  • If possible, start another HTTP server to load balanace requests
    through.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server V7.0 and V8.0 HTTP Plugin on z/OS.   *
    ****************************************************************
    * PROBLEM DESCRIPTION: The WebSphere Application Server        *
    *                      HTTP Plugin could fail to connect       *
    *                      to a backend server and mark that       *
    *                      server down when the server is still    *
    *                      active.                                 *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    If there are more than 2048 socket descriptors in use, the WAS
    plugin could fail to connect to a backend server.  The plugin
    issues a select() after a connect() request goes async, and
    this select could fail if the socket descriptor is greater
    then 2048.
    

Problem conclusion

  • The select() code will be modified to handle a socket
    descriptor of up to 32767.
    
    APAR PM59542 is currently targeted for inclusion in Fix Pack
    7.0.0.25 of WebSphere Application Server V7.0 and Fix Pack
    8.0.0.4 of WebSphere Application Server V8.0.
    
    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

    PM59542

  • Reported component name

    WEBSPHERE FOR Z

  • Reported component ID

    5655I3500

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-03-02

  • Closed date

    2012-04-12

  • Last modified date

    2012-11-02

  • 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 UK81738

       UP12/10/04 P F210

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 #: PM59542

Modified date: 02 November 2012