Here are few very basic and important parameters related to WebLogic Plugin configuration, which we should always keep in mind. Beacuse usually we use Plugins in critical environments where we need LoadBalancing and Failover. It means in large scale applications…so we should be very careful while configuring the Plugin.
There are many Production critical issues which can be resolved just by setting the appripriate values for the below mentioned Parameters…
DynamicServerList (default ON)
WebLogicCluster is only a starting point for the dynamic server list that the server and plug-in maintain
This server list is dynamically updated for every request
If set to OFF:
The plug-in only uses the static list specified with the WebLogicCluster parameter
If one or more servers in the static list fails, the plug-in could waste time trying to connect to a dead server, resulting in decreased performance.
If you add a new server to the cluster, the plug-in cannot proxy requests to the new server unless you redefine this parameter. WebLogic Server automatically adds new servers to the dynamic server list when they become part of the cluster.
WLCookieName (default JSESSIONID)
Name of the WebLogic Server session cookie. By Any Chance if you specify a different cookie Name in your Application’s “weblogic.xml” then you must always set the same CookieName for WLCookieName parameter in your Plugin Configuration file. Or else you will observe that Sessions are getting Lost and users are being redirected to the Login Page while accessing the application.
Idempotent (default ON)
When set to ON and if the servers do not respond within WLIOTimeoutSecs, the plug-in fail over.
If set to OFF the plug-in do not fail over
If you are using the Netscape Enterprise Server Plug-In, or Apache HTTP Server you can set this parameter differently for different URLs or MIME types.
WLDNSRefreshInterval (default 0 Means lookup once)
Specifies number of seconds interval at which WebLogic Server refreshes DNS name to IP mapping for a server.
MaxSkipTime (default 10 seconds)
If a WebLogic Server instance fails, the failed server is marked as “bad” and the plug-in attempts to connect to the next server in the list.
Sets the amount of time after which the plug-in will retry the server marked as “bad.”
The plug-in attempts to connect to a new server in the list each time a unique request is received (that is, a request without a cookie).
MaxSkipTime >= 1
ConnectTimeoutSecs (default 10 seconds)
Maximum time in seconds that the plug-in should attempt to connect to the WebLogic Server host
Make the value greater than ConnectRetrySecs
If ConnectTimeoutSecs expires without a successful connection, even after the appropriate retries (see ConnectRetrySecs), an HTTP 503 (Service Unavailable) response is sent to the client.
ConnectRetrySecs (default 2 seconds)
Interval in seconds that the plug-in should sleep between attempts to connect to the WebLogic server host
ConnectRetrySecs <= ConnectTimeoutSecs
To specify no retries, ConnectRetrySecs = ConnectTimeoutSecs (but the plug-in always attempts to connect at least twice)
KeepAliveSecs (default 20)
The length of time after which an inactive connection between the plug-in and WebLogic Server is closed. You must set KeepAliveEnabled to true (ON when using the Apache plug-in) for this parameter to be effective
The value of this parameter must be less than or equal to the value of the Duration field set in the Administration Console on the Server/HTTP tab, or the value set on the server Mbean with the KeepAliveSecs attribute.
KeepAliveEnabled (default ON)
Enables pooling of connections between the plug-in and WebLogic Server.
Valid values for the Apache plug-in are ON and OFF.
WLIOTimeoutSecs (default 300 seconds)
Also known as HungServerRecoverSecs (old name)
Defines the amount of time the plug-in waits for a response to a request from WebLogic Server
The plug-in waits for WLIOTimeoutSecs for the server to respond and then declares that server dead, and fails over to the next server
The value should be set to a very large value. If the value is less than the time the servlets take to process, then you may see unexpected results
WLSocketTimeoutSecs (default 2 seconds)
Timeout for the socket while connecting
Must be greater than 0
You can tune the number of connection requests that a WebLogic Server instance will accept before refusing additional requests.
This parameter specifies how many TCP connections can be buffered in a wait queue.
This fixed-size queue is populated with requests for connections that the TCP stack has received, but the application has not accepted yet.
By Any chance if you are getting “connection refused” messages when accessing WLS, raise the Accept Backlog by 25% until error disappears.