HTTP Transport default settings could lead to a build-up of connections in CLOSE_WAIT
 Technote (troubleshooting)
 
Problem(Abstract)
The default settings of the HTTP Transport in the Web container service can cause an increase of connections in CLOSE_WAIT status on the Web server and introduce performance issues for the WebSphere® Application Server.
 
Cause
In this case, it might appear that your Application Server is not responding or that the Application Server appears hung. When you view the netstat -an output from the Web server, there are an unexpected number of connections in CLOSE_WAIT:

192.222.1.18.40810   192.222.3.69.9084    25520      0 25520      0 CLOSE_WAIT
192.222.1.18.40811   192.222.3.69.9084    25520      0 25520      0 CLOSE_WAIT

 
Resolving the problem
This problem presents itself because the default settings for the Web container I/O timeout and keep alive timeout have been set too low.

There are three options to pursue when facing this issue:

  • Use a threaded Web server such as IBM® HTTP Server 2.0. This issue has primarily been observed when using a process-based Web server such as IBM HTTP Server 1.3.26.
  • Disable the use of the keep alive connections by setting the value for Maximum keep alive to 0.
  • Tune the values for KeepAliveTimeout and I/O TimeOut. The default values are 5 seconds. We have suggested testing values between 15 and 60 seconds for optimum performance.

To change the values in 4.0

From the administrative console, select Application Server > Services > Web Container Service > Edit Properties > Transport Tab


To change the values in 5.0

  1. Access the settings page for a property of the transport:

    1. In the console navigation tree, click Servers > Application Servers > server_name > Web Container > HTTP Transports > transport_host_name > Custom Properties.

    2. On the Custom Properties page, click New.

  2. On the settings page for a property, specify the transport property name and the value.

    1. For example, specify a name of MaxKeepAliveConnections and a value 0.

    2. Click OK.

    • To modify the I/O timeout use ConnectionIOTimeout as the name.

    • To modify the keep alive timeout use ConnectionKeepAliveTimeout as the name.

  3. Click Save on the console taskbar and save the changes to the configuration.

  4. Restart the server.
 
 
Cross Reference information
Segment Product Component Platform Version Edition
Application Servers Runtimes for Java Technology Java SDK
 
 


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > HTTP Transport
Operating system(s): Windows
Software version: 5.0
Software edition:
Reference #: 1110697
IBM Group: Software Group
Modified date: Mar 27, 2006