DOCUMENT:Q194892  24-FEB-1999  [winnt]
TITLE   :Load-Balanced Application Does Not Work Properly Using WLBS
PRODUCT :Microsoft Windows NT
PROD/VER:winnt:4.0
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft Windows NT Server version 4.0 
 - Microsoft Windows NT Load Balancing Service 
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SUMMARY
=======

An application that is load balanced does not appear to work correctly when
running Windows NT Load Balancing Service (WLBS).

 - All of the application's ports are not being load balanced. Some applications
   require multiple ports to perform their functions. For example, FTP uses
   ports 20 and 21. If both ports are not load balanced (usually with one port
   rule), the application will not work correctly. Check that the applicable
   port rule covers all ports used by the application and be sure to enable
   client affinity (single or Class C).

 - The application is not started on all cluster hosts. WLBS does not start or
   control applications. You should check that the application has been started
   on every cluster host. If an application fails, you can disable its
   associated port range using the wlbs disable command.

 - The application should not be load balanced. Applications that update a file
   on the local cluster host may not work correctly when load balanced because
   multiple instances of the application may conflict when attempting to update
   a common file. For example, e-mail, groupware, and database servers often
   have this problem. Do not load balance an application until its data sharing
   requirements are thoroughly understood and met.

 - The application is not a TCP/IP service. WLBS load balances applications by
   distributing incoming client requests among the cluster hosts. If a server
   application is not structured as a TCP/IP service that receives client
   requests, it will not benefit from using WLBS, and you will not observe load
   balancing.

 - Your firewall is proxying client traffic and making it appear as if all
   connections are originating from the same client IP address. If the load
   balancing rule is configured with Single affinity, all traffic will be
   handled by the same cluster host. Turn off address translation (proxying) on
   the firewall or change affinity from Single to None.

   NOTE: You may need Single affinity to provide session support.

Additional query words: WLBS Convoy

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Keywords          :  
Technology        : kbWinNTsearch kbWinNT400xsearch kbWinNTSsearch kbWinNTS400xsearch kbWinNTS400 kbWinNTLBSSearch
Version           : winnt:4.0
Issue type        : kbinfo

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