Workload is not getting distributed

Overview

For canonical tips: Troubleshooting Workload Management (WLM) problems in WebSphere Application Server

HTTP requests are not distributed to all servers

If HTTP requests are not being distributed to all servers:

• Check the Primary Servers list.

  The plug-in load balances across all servers defined in the Primary Servers list, if affinity has not been established. If we 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.

• Try setting IgnoreAffinity=false

• 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. Use the console to ensure that the affected server is running.

Enterprise bean 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 console to verify that the server is started. Try starting it, or if started, stop and restart it.

• Browse the 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 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.

Enterprise bean 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

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.

(zos) 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.

(zos)

• 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)

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. 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.

• (zos) 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.

• (zos) 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.

(zos) 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.

We 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.

A cluster does not fail over to its backup cluster

We might experience an error that is similar to the following sample:

[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"

Perform the following steps to fix the configuration:

1. Review the deployment manager hostname and bootstrap port for each backup cluster setting.

2. Review the core group bridge peer ports to make sure the hostname and distribution and consistency services (DCS) port are accurate.

3. Verify that the names of the primary and backup clusters match.

4. If the application is going through security to go to the backup cluster, review the security configuration. We might need to use single sign on (SSO) and import the LTPA> (LTPA) keys to the backup cell.

Other troubleshooting steps

1. Browse the JVM logs of the problem deployment manager and application servers:

   1. Look up any error messages by selecting the Reference view of the information center navigation and expanding Messages in the navigation tree.

   2. 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...
      app_server_root/logs

   3. 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. 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.

2. Ensure that all the machines in the configuration have TCP/IP connectivity to each other by running the ping command:

   1. From each physical server to the deployment manager

   2. From the deployment manager to each physical server

3. 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:

   1. 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 clientand Cannot look up an object hosted by the product from a servlet, JSP file, or other clienttopics.

   2. If problems seem to appear after enabling security, review the Errors or access problems after enabling security topic.

   3. 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.

   4. 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.

   5. If we have problems installing or deploying an application on servers on one or more nodes, review the Troubleshooting code deployment and installation problems topic.

4. If the 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.

5. Check for troubleshooting tips for the workload management component.

6. Check to see if the problem is identified and documented by looking at available online support (hints and tips, technotes, and fixes).

HPEL

This topic references one or more of the application server log files. As a recommended alternative, we can configure the server to use the High Performance Extensible Logging (HPEL) log and trace infrastructure instead of using SystemOut.log , SystemErr.log, trace.log, and activity.log files on distributed and IBM i systems. We can also use HPEL in conjunction with the native z/OS logging facilities. If we are using HPEL, we can access all of the log and trace information using the LogViewer command-line tool from the server profile bin directory. See the information about using HPEL to troubleshoot applications for more information on using HPEL.

Related tasks

Troubleshooting administration

View JVM logs

Add logging and tracing to the application

Multiserver environment errors

Workload management component troubleshooting tips

Naming service troubleshooting tips

Application access problems

Enterprise bean cannot be accessed from a servlet, a JSP file, a stand-alone program, or another client

Application client SOAP request troubleshooting tips

Web module or application server stops processing requests

Application deployment problems

Web server plug-in troubleshooting tips

Web resource is not displayed

Access problems after enabling security