Workload not getting distributed
What kind of problem are you seeing?
If none of these problem solution descriptions fixes your problem:
- Browse the of the problem deployment
manager and application servers:
- Look up any error messages by selecting the Reference view of the
information center navigation and expanding Messages in the navigation
tree.
If Java exceptions appear in the log files, try to determine the actual
subcomponent directly involved in the problem by examining the trace stack
and looking for a WebSphere Application Server-related class near the top
of the stack (names beginning with com.ibm.websphere or com.ibm.ws)
that threw the exception. If appropriate, review the steps for troubleshooting
the appropriate subcomponent under the Troubleshooting
by component: what is not working? topic.
For example, if the
exception appears to have been thrown by a class in the com.ibm.websphere.naming package,
review the Naming Services
Component troubleshooting tips topic.
- Ensure that all the machines in your configuration have TCP/IP connectivity
to each other by running the ping command:
- From each physical server to the Deployment Manager
- From the Deployment Manager to each physical server
- Although the problem is happening in a clustered environment, the actual
cause might be only indirectly related, or unrelated, to clustering. Investigate
all relevant possibilities:
- If an enterprise bean on one or more servers is not serving requests,
review the Cannot access
an enterprise bean from a servlet, JSP, stand-alone program, or other client and Cannot access an object hosted
by WebSphere Application Server from a servlet, JSP file, or other client topics.
- If problems seem to appear after enabling security, review the Errors or access problems after enabling security topic.
- If an application server stops responding to requests, or spontaneously
dies (its process closes), review the Web
module or application server dies or hangs topic.
- If SOAP requests are not being served by some or all servers, review the Errors returned to client trying
to send a SOAP request topic.
- If you have problems installing or deploying
an application on servers on one or more nodes, review the Troubleshooting code deployment
and installation problems topic.
- If your topology consists of a Windows-based
Deployment Manager with UNIX-based servers, browse any recently-updated .xml and .policy files
on the UNIX-based platform using vi to ensure that Control-M characters
are not present in the files. To avoid this problem in the future, edit these
files using vi on the UNIX-based platform, to avoid inserting these
characters.
- Check the steps for troubleshooting the Workload
Management component.
- Check to see if the problem is identified and documented by looking at available online support (hints and
tips, technotes, and fixes).
Web (HTTP) requests are not distributed to all
servers
If HTTP requests are not being distributed to all servers:
- Check your PrimaryServers list. The plug-in load balances across all servers
that are defined in the PrimaryServers list, if affinity has not been established.
If you do not have a PrimaryServers list defined, the plug-in load balances
across all servers defined in the cluster, if affinity has not been established.
In the case where affinity has been established, the plug-in should go directly
to that server, for all requests within the same HTTP session.
- If some servers are servicing requests and one or more others are not,
try accessing a problem server directly to verify that it works, apart from
workload management issues. If that does not work:
- See the article HTTP plug-in component troubleshooting tips for
more information.
- Check the steps for diagnosing workload
management issues in Troubleshooting
the Workload Management component.
EJB requests are not distributed to all servers
If
a client cannot reach a server in a cluster thought to be reachable, a server
might be marked unusable, or is down. To verify this:
- Use the administrative console to verify that the server is started. Try
starting it, or if started, stop and restart it.
- Browse the administrative console and verify that the node that runs the
server having the problem appears. If it does not:
- If possible, try accessing the enterprise bean directly on the problem
server to see if there is a problem with TCP/IP connectivity, application
server health, or other problem not related to workload management. If this
fails, review the topic Cannot
access enterprise bean from a servlet, JSP, stand-alone program , or other
client.
- Check the steps for diagnosing workload
management issues in the Troubleshooting the Workload Management component topic.
EJB requests
are not distributed evenly
There are a number of possible reasons
for this behavior, which generally fall into one or more of these categories:
- Improper configuration
- Environment issues such as the availability of servers or applications.
- A large numbers of requests that involve transactional affinity, or
- A small number of clients
Work load management of WebSphere Application Server is based
on a round robin scheme of request distribution. This results in balance being
determined by numbers of requests rather than by any other measure. A true
balance problem is determined by comparing the number of requests processed
by each member of the cluster with the weights that have been set for each
of those members. This is done by following
the steps in the Troubleshooting the Workload Management component topic.
- When the percentage of requests that arrive for each member of the cluster
is consistent with the weights then further analysis of the application is
required to determine the cause for the workload being imbalanced even when
the number of requests is balanced.
- When the number of numIncomingNonWLMObjectRequests is not balanced
among the members of the cluster and is large in relation to the numIncomingRequests then
the reason for the imbalance is the non-distributable components installed
on the members of the cluster. A modification to the configuration will yield
a more balanced environment.
- When the number of numIncomingStrongAffinityRequests is not balanced
among the members of the cluster and is large in relation to the numIncomingRequests then
the reason for the imbalance is the requests which are invoked within a transaction.
These can be reduced by installing the objects involved within a transaction
within the same cluster.
A failing server still receives enterprise bean
requests (failover fails)
Some possible causes of this problem are:
- The client might have been in a transaction with an enterprise bean on
the server that went down. of the application server hosting the problem enterprise bean
instance. If a request is returned with CORBA SystemException COMM_FAILURE
org.omg.CORBA.completion_status.COMPLETED_MAYBE, this might be working
as designed. The design is to let this particular exception flow back to the
client, since the transaction might have completed. Failing over this request
to another server could result in this request being serviced twice.
- If the requests sent to the servers come back to the client with any other
exceptions consistently, it might be that no servers are available. In
this case, follow the resolution steps as outlined in Troubleshooting the Workload Management component.
Stopped or hung servers
do not share the workload after being restored
This error occurs
when the servers that were unavailable are not recognized by the Workload
Management component after they are restored. There is an unusable interval
determined by the property com.ibm.websphere.wlm.unusable.interval during
which the workload manager waits to send to a server that has been marked
unusable. By default this is 15 minutes.
You can confirm that this is
the problem by ensuring that servers
that were down are now up and capable of servicing requests. Then
wait for the unusable interval to elapse before checking to determine whether
failover occurs.
For current information available from IBM Support on known problems
and their resolution, see the IBM Support
page.
IBM Support has documents
that can save you time gathering information needed to resolve this problem.
Before opening a PMR, see the IBM Support
page.

Troubleshooting by task: What are you trying to do?
Troubleshooting by component: What is not working?

Troubleshooting application runtime and management problems
Errors setting up multiserver environments
Workload Management component troubleshooting tips
Searchable topic ID:
rtrb_wlmprobs
Last updated: Jun 21, 2007 8:07:48 PM CDT
WebSphere Business Integration Server Foundation, Version 5.0.2
http://publib.boulder.ibm.com/infocenter/wasinfo/index.jsp?topic=/com.ibm.wasee.doc/info/ee/ae/rtrb_wlmprobs.html