Troubleshoot high availability environment problems

Review the following topics if you encounter a problem with your high availability environment.

Message HMGR0218I is not displayed after a Java Virtual Machine starts

In a properly set up high availability environment, a high availability manager can reassess the environment it is managing and accept new components as they are added to the environment. For example, when a Java virtual machine (JVM) is added to the infrastructure, a discovery process begins. During startup the JVM tries to contact the other members of the core group. When it finds another running JVM, it initiates a join process with that JVM that determines whether or not the JVM can join the core group. If the new JVM is accepted as a member of the core group, all of the JVMs, including the new one, log message HMGR0218I . This message is also displayed on the administrative console.

Message HMGR0218I indicates the number of application servers in the core group that are currently online. If this message is not displayed after a JVM starts, either a configuration problem or a communication problem has occurred. To fix this situation, verify that the application server is running on a current configuration, by either using the deployment manager to tell the node agent to synchronize, or use the syncNode command o manually perform the synchronization. If the JVM still cannot join the core group, a network configuration problem exists.

CPU starvation messages in SystemOut.log

CPU starvation detected error messages are displayed in the SystemOut.log file whenever there is not enough physical memory available to allow the high availability manager threads to have consistent runtimes. When the CPU is spending the majority of its time trying to load swapped-out processes while processing incoming work, thread starvation might occur. The high availability manager detects this condition, and logs these error messages informing you that threads are not getting the required runtime.

To achieve good performance and avoid receiving these error messages, it is recommended that you allocate at least 512 MB of RAM for each Java process running on a single machine.

High CPU usage in a large cell configuration when security is enabledWith certain configurations and states, the amount of time spent in discovery becomes substantial.

• If a large the number of processes are defined within a core group, a proportionally large number of connections must be established to support these processes.

• If a large number of inactive processes are defined within a core group, a proportionally large number of connections are attempted during each discovery interval.

• If global security is enabled, the DCS connections are secured, and the impact of opening a connection greatly increases .

To decrease the CPU time spent in discovery:

1. In the administrative console, click Servers > Core groups > Core groups settings , and then select the -> DefaultCoreGroup.

2. Under Additional Properties, click Custom properties > New.

3. Enter IBM_CS_UNICAST_DISCOVERY_INTERVAL_SECS in the Name field and 120 in the Value field.

4. Click OK.

5. Then click New again and enter IBM_CS_SS_SECURE_TOKEN in the Name field andfalse in the Value field.

6. Click OK and then Save to apply these changes to the master configuration.

7. Restart the server for these changes to take effect.

Related tasks

Related reference

syncNode command

Searchable topic ID: rtrb_ha_env_trbl