Web server plug-in tuning tips

Important tips for Web server plug-in tuning include how to balance workload and improve performance in a high stress environment. Balancing workloads among application servers in a network fronted by a Web server plug-in helps improve request response time.

Balancing workloads

The WebSphere Application Server uses the z/OS native Workload Management (WLM) functionality to dynamically balance the workload of application servers defined to a z/OS HTTP Server. See the z/OS publication HTTP Server Planning, Installing and Using v5.3 for more information.

Limiting the number of connections that can be established with an application server works best for Web servers that follow the threading model instead of the process model, and only one process is started.

The IBM HTTP Server V6.0.x follows the threading model. To prevent the IBM HTTP Server from starting more than one process, change the following properties in the Web server configuration file (httpd.conf) to the indicated values:

ServerLimit           1
ThreadLimit           4000
StartServers          1
MaxClients            1024
MinSpareThreads       1
MaxSpareThreads       1024
ThreadsPerChild       1024
MaxRequestsPerChild   0

Improving performance in a high stress environment

To tune the TcpTimedWaitDelay setting, change the value of the tcp_time_wait_interval parameter from the default value of 240 seconds, to 30 seconds:
  1. Locate in the Windows Registry:
    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\tcpip\Parameters\TcpTimedWaitDelay
    If this entry does not exist in your Windows Registry, create it by editing this entry as a new DWORD item.
  2. Specify, in seconds, a value between 30 and 300 inclusive for this entry. (It is recommended that you specify a value of 30. )
To tune the MaxUserPort setting:
  1. Locate in the Windows Registry:
    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\tcpip\Parameters\MaxUserPort
    If this entry does not exist in your Windows Registry, create it by editing this entry as a new DWORD item.
  2. Set the maximum number of ports to a value between 5000 and 65534 ports, inclusive. (It is recommended that you specify a value of 65534,)

See the Microsoft Web site for more information about these settings.




Related tasks
Tuning the WebSphere Application Server for z/OS runtime
Communicating with Web servers
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Last updated: Aug 29, 2010 8:25:23 PM CDT
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