WebSphere Application Server - Express, Version 6.0.x     Operating Systems: AIX, HP-UX, Linux, Solaris, Windows

Web server plug-in tuning tips

Balancing workloads

When this maximum number of connections is reached, the plug-in, when establishing connections, automatically skips that application server, and tries the next available application server. If no application servers are available, an HTTP 503 response code will be returned to the client. This code indicates that the server is currently unable to handle the request because it is experiencing a temporary overloading or because maintenance is being performed.

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
[Windows]

Improving performance in a high stress environment

If you use the default settings for a Microsoft Windows operating system, you might encounter Web server plug-in performance problems if you are running in a high stress environment. To avoid these problems, consider tuning the the TCP/IP setting for this operating system. Two of the keys setting to tune are TcpTimedWaitDelay and MaxUserPort.

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
Communicating with Web servers

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Last updated: Jun 8, 2005 12:45:23 PM EDT
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