Workload is not getting distributed
This information might help you diagnose the trouble if you are having a workload distribution problem.
- HTTP requests are not distributed to all servers
- Enterprise bean requests are not distributed to all servers
Enterprise bean requests are not distributed evenly
- A failing server still receives enterprise bean requests (failover is not completed)
- Stopped or hung servers do not share the workload after being restored
A cluster does not fail over to its backup cluster
Browse the JVM logs 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.
Use the Log and Trace Analyzer toolt o browse and analyze the service log (activity.log) of the deployment manager and any nodes encountering problems. View the activity.log files in both app_server_root/logs and app_server_root/logs.
Analyze the service log (activity.log) of the deployment manager and any nodes encountering problems. View the activity.log files in profile_root/logs.
If Java™ exceptions appear in the log files, try to determine the actual subcomponent that is directly involved in the problem by examining the trace stack and looking for a product-related class near the top of the stack (names beginning with com.ibm.websphere or com.ibm.ws) that created the exception. If appropriate, review the steps for troubleshooting the appropriate subcomponent in the Troubleshooting WebSphere applications section of the Information Center.
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.
Browse the JVM logs 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 that is directly involved in the problem by examining the trace stack and looking for a product-related class near the top of the stack (names beginning with com.ibm.websphere or com.ibm.ws) that created the exception. If appropriate, review the steps for troubleshooting the appropriate subcomponent under the Troubleshooting WebSphere applications section of the Information Center.
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 look up an object hosted by the product 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 supported UNIX systems servers, browse any recently-updated .xml and .policy files on the supported UNIX-based systems 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 supported UNIX-based systems, to avoid inserting these characters.
Check for troubleshooting tips for 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).
HTTP requests are not distributed to all servers
- Check your Primary Servers list. The plug-in load balances across all servers that are defined in the Primary Servers list, if affinity has not been established. If you do not have a Primary Servers 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:
- Use the administrative console to ensure that the affected server is running.
- See the topic Web resource does not display for more information.
- See the HTTP plug-in component troubleshooting tips topic for more information.
Check the steps for diagnosing workload management issues in the Troubleshooting the Workload Management component topic.
Enterprise bean requests are not distributed to all servers
- 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:
- Review the steps for adding a node to a cluster.
- Review the steps in the section One or more nodes do not show up in the administrative console.
- 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 Cannot access enterprise bean from a servlet, JSP, stand-alone program , or other client topic.
Check the steps for diagnosing workload management issues in the Troubleshooting the Workload Management component topic.
![[AIX Solaris HP-UX Linux Windows]](../images/dist.gif)
![[IBM i]](../images/iseries.gif)
Enterprise bean requests are not distributed evenly
- 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
Workload management in the product
is based on a weighted proportional scheme to spray requests among
the servers. 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 topic
Troubleshooting the Workload Management component.
Workload
management in the product 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.
![[z/OS]](../images/ngzos.gif)
- 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 is not completed)
The client might have been in a transaction with an enterprise bean on the server that went down. Check the JVM logs 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.
The client might have been in a transaction with an enterprise bean on the server that went down. Check the JVM logs 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 the topic Troubleshooting the Workload Management component.
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.
![[z/OS]](../images/ngzos.gif)
Stopped or hung servers do not share the workload after being restored
This error occurs when previously unavailable servers are not recognized by the workload management component after those servers 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 5 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.
![[AIX Solaris HP-UX Linux Windows]](../images/dist.gif)
![[IBM i]](../images/iseries.gif)
A cluster does not fail over to its backup cluster
[10/11/04 13:11:10:233 CDT] 00000036 SelectionMana A WWLM0061W: An error was
encountered sending a request to cluster member {MEMBERNAME=FlorenceEJBServer1,
NODENAME=fwwsaix1Node01} and that member has been marked unusable for future
requests to the cluster "", because of exception: org.omg.CORBA.COMM_FAILURE:
CONNECT_FAILURE_ON_SSL_CLIENT_SOCKET - JSSL0130E: java.io.IOException: Signals
that an I/O exception of some sort has occurred. Reason: Connection refused
vmcid: 0x49421000 minor code: 70 completed: No"
- Review your deployment manager hostname and bootstrap port for each backup cluster setting.
- Review your core group bridge peer ports to make sure the hostname and distribution and consistency services (DCS) port are accurate.
- Verify that the names of your primary and backup clusters match.
- If your application is going through security to go to the backup cluster, review your security configuration. You might need to use single sign on (SSO) and import the Lightweight Third Party Authentication (LTPA) keys to the backup cell.