HTTP plug-in cluster properties

Use this page to view or change HTTP plug-in properties that apply to the cluster. To view this console page, click Servers > Clusters > WebSphere application servers clusters > cluster_name > Web server plug-in cluster properties.


Server read/write timeout retry value

Limit for the number of times the HTTP plug-in retries an HTTP request that has timed out, due to ServerIOTimeout. The default value, -1, indicates that no additional limits apply to the number of retries. A 0 value indicates there are no retries. Retries are always limited by the number of available servers in the cluster.

Important: This directive does not apply to connection failures or timeouts due to the HTTP plug-in ConnectTimeout.

If memory-to-memory session replication is configured for this cluster, set getDWMTable to true to ensure that the HTTP plug-in always has the latest dynamic information about cluster members.


Cluster address

Name of the cluster address.

Specify whether to enable secure or nonsecure protocol, along with the host, port, keyring, and stash.

The optional cluster address setting specifies the address of an HTTP load balancer, where to route non-affinity requests, instead of load balancing between normal cluster members. Ensure that the transport points to a load balancing device that intelligently routes to the same members, as defined in the cluster. On subsequent requests with affinity, the load ClusterAddress is not used and the HTTP plug-in directly contacts the proper member.


Connection timeout

Whether there is a time limit for how long the plug-in waits to send a request to or receive a response from the application server.

This field corresponds to the ConnectionTimeout element in the plugin-cfg.xml file.

The setting for this field determines whether the plug-in performs non-blocking connections with the application server. Non-blocking connections are beneficial when the plug-in is unable to contact the destination to determine whether or not the port is available.

If the Use connection timeout setting is not selected, the plug-in performs nonblocking connections with the application server. If the Use connection timeout setting is selected, specify a value in the seconds field:

Information Value
Data type Integer
Default Default 0 for the first application server (server1) of a profile, and 5 for all of the other application servers of a profile.


Read/write timeout

Whether there is a time limit for how long the plug-in waits to send a request to or receive a response from the application server.

This field corresponds to the ServerIOTimeout element in the plugin-cfg.xml file.

Select the Use read/write timeout property to set a read/write timeout. When you select this setting, specify the length of time, in seconds that the plug-in waits to send a request or to receive a response. When selecting a value to specify for this field, remember that it might take a couple of minutes for an application server to process a request. Setting the value too low might cause the plug-in to send a false server error response to the client. If the check box is not checked, the plug-in uses blocked I/O to write requests to and read responses from the application server until the TCP connection times out.

The Use read/write timeout setting on the console corresponds to the ServerIOTimeout attribute in the plugin-cfg.xml file. The default value for this setting is different from the default value in previous versions of the product.

Information Value
Data type Integer
Default 900 seconds


Maximum number of connections

Maximum number of pending connections to an Application Server that can be flowing through a web server process at any point in time.

This field corresponds to the ServerMaxConnections element in the plugin-cfg.xml file.

Select the Use maximum number of connections property to set a maximum number of connections. When you select this setting, you, must specify the maximum number of connections that can exist between the web server and the application server at any given point in time.

For example, assuming that:

In this example, the application server could potentially get up to 500 connections. (You take the number of nodes, 5, multiply it by the number of processes, 2, and then multiply that number by the number specified for this property, 50, for a total of 500 connections.

If either zero or -1, there is no limit to the number of pending connections to the Application Servers.

(zos) This attribute is ignored on the z/OS platform. The z/OS controller, working with WLM, handles new connections dynamically.

Information Value
Data type Integer
Default 0


Use extended handshake to check whether application server is running

When selected, the web server plug-in cluster uses an extended handshake to check whether the application server is running.

This field corresponds to the ExtendedHandshake element in the plugin-cfg.xml file.

Select this property if a proxy firewall is between the plug-in and the application server.

The plug-in marks a server as down when the connect() fails. However, when a proxy firewall is in between the plug-in and the application server, the connect() will succeed, even though the back end application server is down. This causes the plug-in to not failover correctly to another application server.

If the plug-in performs some handshaking with the application server to ensure that the application server is started before the plug-in sends a request, the plug-in can failover to another application server if it detects that the application server with which it is attempting to perform a handshake is not available.

By default, this field is not selected. Select this field to use extended handshake to check whether an application server is running.


Send the header "100 Continue" before sending the request content

Whether the web server plug-in cluster sends the header "100 Continue" to the application server before it sends the request content.

This field corresponds to the WaitForContinue element in the plugin-cfg.xml file.

When selected, the web server plug-in sends the header "100 Continue" to the application server before it sends the request content.

By default, this field is not selected. Select this field to enable this function.


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