What kind of problem are you seeing?
If none of these problem solution descriptions fix your problem:
- 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 Analyzer tool to 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.
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 WebSphere Application Server-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
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 Workload management component troubleshooting tips.
- 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.
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 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.
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 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 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.
- 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.
A cluster does
not fail over to its backup cluster
You 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 your configuration:
- 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
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.
If you do not find your problem listed there, contact IBM Support.
For current information available from IBM Support on known
problems and their resolution, see the IBM Support page. You should also refer to this page
before opening a PMR because it contains documents that can save you time
gathering information needed to resolve a problem.