Application Server property settings for a Web server plug-in

 

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Use this page to view or change application server settings for a Web server plug-in.

To view this administrative console page, click...

Application Servers | servername | Web Server Plug-in

On the Configuration tab, one can edit fields. On the Runtime tab, one can look at read-only information.

The Runtime tab is available only when this Web server has accessed applications running on application servers and there is an http_plugin.log file.

 

Configuration tab

Server role

Specifies the role this application server is assigned.

Select Primary to add this application server to the list of primary application servers. The plug-in initially attempts to route requests to the application servers on this list.

Select Backup to add this application server to the list of backup application servers. The plug-in does not load balance across the backup application servers. A backup server is only used if a primary server is not available. When the plug-in determines that a backup application server is required, it goes through the list of backup servers, in order, until no servers are left in the list or until a request is successfully sent and a response received from one of the servers on this list.

Connect timeout

Specifies whether or not there is a limited amount of time the Application Server will maintain a connection with the Web server.

We can select either No timeout or Set timeout. If you select Set timeout you, must specify, in seconds, the length of time a connection with the Web server is to be maintained.

This property enables the plug-in to perform 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 no value is specified for this property, the plug-in performs a blocking connect in which the plug-in sits until an operating system times out (which could be as long as 2 minutes depending on the platform) and allows the plug-in to mark the server unavailable.

A value of 0 causes the plug-in to perform a blocking connect. A value greater than 0 specifies the number of seconds you want the plug-in to wait for a successful connection. If a connection does not occur after that time interval, the plug-in marks the server unavailable and fails over to another application server defined for the requested application.

Data type Integer

Maximum number of connections that can be handled by the Application Server

Specifies the 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.

We can select either No limit or Set limit. If you select Set limit 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:

  • The application server is fronted by 5 nodes that are running an IHS Web server.
  • Each node starts 2 processes.
  • This property is set to 50.

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

Data type Integer
Default -1

Use extended handshake to check whether Application Server is running

When selected, the Web server plug-in will use an extended handshake to check whether or not the Application Server is running.

This field corresponds to the ServerExtendedHandshake 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 other application servers.

If the plug-in performs some handshaking with the application server to ensure that it is started before it sends a request it can failover to another application server if it detects that the application server with which it is attempting to perform a handshake is down.

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

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

When selected, the Web server plug-in will send the header "100 Continue" to the Application Server before it sends the request content.