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7.2 Managing workloads >
7.2.6 Tuning a workload management configuration
7.2.6 Tuning a workload management configuration
The workload management service uses several parameters to control the behavior of the
workload management run time. In the majority of cases, you do not need to explicitly set
the values of these parameters. However, if you are experiencing problems with your
workload management configuration, you can adjust these properties to tune the behavior of
the workload management run time.
Set the values of these properties only in
response to problems that you encounter in your environment. If workload management is
functioning correctly, changing these properties can produce undesirable results.
Workload management client properties
A workload management client can be a cloned resource or an application server that
acts as an EJB client to a cloned resource. The following properties can be used to
control the behavior of the workload management client run time. They are set as
command-line arguments for the Java Virtual Machine (JVM) process in which the workload
management client is running. In many cases, such as where a servlet is a client to an
enterprise bean, this means that these parameters are specified as part of the command-
line arguments for the application server where the servlet is running.
- com.ibm.CORBA.requestTimeout. This property specifies the timeout
period for responding to workload management requests. Set this value in the Command
Line Arguments field by using the -D option as follows:
-Dcom.ibm.CORBA.requestTimeout=timeout_interval
where timeout_interval is the timeout period in seconds. If your network is
subject to extreme latency, specify a large value to prevent timeouts. If you specify a
value that is too small, an application server that particpates in workload management can
ttime out before it receives a response.
Be very careful when
you specify this property: it has no recommended value. Set it only if your application is
experiencing problems with timeouts.
- com.ibm.ejs.wlm.MaxCommFailures. This property specifies the number of
attempts that a workload management client makes to contact the administrative server that
manages workloads for the client. The workload management client run time does not
identify an administrative server as unavailable until a certain number of attempts to
access it have failed. This allows workload management to continue if the server suffers
from transient errors that can briefly prevent it from communicating with a client.
However, it can also propagate nontransient administrative server failures to the
client. Set this value in the Command Line Arguments field in the
administrative console by using the -D option as follows:
-Dcom.ibm.ejs.wlm.MaxCommFailures=max_failures
where max_failures specifies how many times the client attempts to contact the
administrative server after the first failure. The default value is zero, which
means that the workload management run time does not attempt to use the administrative
server after the first failure until a timeout interval (specified by the com.ibm.ejs.wlm.UnusableInterval
parameter) expires. This reduces the possibility of further server failures being
propagated to the client.
- com.ibm.ejs.wlm.UnusableInterval. This property specifies the time
interval that the workload management client run time waits after it marks an
administrative server as unavailable before it attempts to contact the server again. Set
this value in the Command Line Arguments field in the administrative
console by using the -D option as follows:
-Dcom.ibm.ejs.wlm.UnusableInterval=interval
where interval is the time in seconds between attempts. The default
value is 900 seconds. If this parameter is set to a large value, the server is marked as
unavailable for a long period of time. This prevents the workload management refresh
protocol from refreshing the workload management state of the client until after this time
period has ended.
Administrative server properties
The administrative server for the cloned resources that participate in a workload
managment group (such as an application server cluster) acts as the workload management
server.
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