Definitions:
Cluster:
A set of application servers that are managed together and participate in
workload management. The application servers that are members of a cluster
can be on the same or on separate nodes.
Weight:
The number of requests that each cluster member will receive. This
parameter is used to estimate the percent of requests that this cluster
member will receive. For example, consider two cluster members, A and B.
The weight for cluster member A is equal to three and the weight for
cluster member B is equal to one. Cluster member A will receive about 75%
of the requests.
Prefer Local:
Enabling the Prefer Local setting in the cluster routes the request to the
local node, if possible, before going to the other cluster members. This
routing setting does not mean that the request stays in that cluster
member Java(TM) virtual machine (JVM), but rather on that cluster member
node.
Horizontal Cluster Members:
Application servers that are part of a cluster that spans multiple nodes.
Vertical Cluster Members:
Application servers that are part of a cluster that does not span multiple
nodes.
Scenarios:
Stand-alone Application
Design: A client application with the complete V5.0
client installation or a WebSphere Application Server V5.0 installation on
the same machine that is the only supported V5.0 Java client. You can use
the launchclient script that is located in the $WAS_HOME/bin
directory or when you run the java command, make sure that you
include all the WebSphere libraries, for example:
"-Djava.ext.dirs=%WAS_HOME%\java\lib;%WAS_HOME%\java\jre\lib\ext;%WAS_HOME%\classes;%WAS_HOME%\lib".
The client connects to the EJB container of the cluster and workload
manages the request to all the cluster member enterprise beans, based on
the weights and settings. The lookup and method calls will be the only
request that are enterprise bean workload-managed.
Tracing: To trace what is happening with the Java
client:
- Add the following argument to the java command:
"-DtraceSettingsFile=ClientTraceSettings.properties".
- Make a properties file called "ClientTraceSettings.properties" using
the "TraceSettings.properties" file located in the
$WAS_HOME/properties directory as a template.
- Enable tracing on each cluster member to see what is happening on the
other side.
Combined Web and EJB container cluster members
Design: If the EJB container and Web container are on the
same cluster member, then you will not see EJB workload management. IBM
Developer Kit process optimization overrides the EJB workload management
in V5.0. There is no way to remove this V5.0 design.
Separate Web container and EJB container servers
Design: Creating application servers with servlets that
call enterprise beans in a cluster. In this scenario, the Web container
that the client is on and the EJB container are on separate servers,
showing you the EJB workload management capabilities of V5.0. The Web
container connects to the EJB container of the cluster and manages the
request to all the cluster member enterprise beans, based on the weights
and settings. The lookup and method calls are the only requests that are
enterprise bean workload-managed.
Tracing: Enable tracing on both the cluster members
individually and the application server that contains the servlets that
are calling the enterprise beans.
Help
If you are having a problem, refer to the WebSphere Application Server
V5.0 Information Center:
http://publib7b.boulder.ibm.com/webapp/wasinfo1/index.jsp?deployment=NetworkDeployment
This site has many helpful links. Look at the "Workload Management
component troubleshooting tips" located under the "Monitoring and
troubleshooting" -> "Problems" -> "Troubleshooting by components:
What is not working?" section.
If you still cannot find the information you are looking for, call
800-IBM-SERV.
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