Probing Algorithm and Functionality

The Sun Cluster HA for WebSphere Message Broker fault monitor is controlled by the extension properties that control the probing frequency. The default values of these properties determine the preset behavior of the fault monitor. The preset behavior should be suitable for most Sun Cluster installations. Therefore, you should tune the Sun Cluster HA for WebSphere Message Broker fault monitor only if you need to modify this preset behavior.

• Setting the interval between fault monitor probes (Thorough_probe_interval)

• Setting the timeout for fault monitor probes (Probe_timeout)

• Setting the number of times the fault monitor attempts to restart the resource (Retry_count)

The Sun Cluster HA for WebSphere Message Broker fault monitor checks the broker and other components within an infinite loop. During each cycle the fault monitor will check the relevant component and report either a failure or success.

If the fault monitor is successful it returns to its infinite loop and continues the next cycle of probing and sleeping.

If the fault monitor reports a failure a request is made to the cluster to restart the resource. If the fault monitor reports another failure another request is made to the cluster to restart the resource. This behavior will continue whenever the fault monitor reports a failure.

If successive restarts exceed the Retry_count within the Thorough_probe_interval a request to failover the resource group onto a different node or zone is made.

Operations of the Broker probe

The broker probe can check the broker by using a simple message flow test, if SC3_IN and SC3_OUT are set to the inbound and outbound queues.

If set, the broker probe puts a message to the inbound queue referenced by the SC3_IN variable. After waiting two seconds, the broker probe checks that the message has arrived at the outbound queue referenced by the SC3_OUT variable.

If SC3_IN and SC3_OUT are set to NONE the simple message flow is not performed. Instead the broker probe checks that the bipservice process is still running.

SC3_IN and SC3_OUT are set when the broker resource was configured and registered within /opt/SUNWscmqi/sib/util/sib_config.

Operations of the Configuration Manager probe

The broker probe checks the configuration manager to see if the bipservice process is still running.

The configuration manager resource must set SC3_IN and SC3_OUT to NONE. This ensures that the simple message flow test is not performed.

Operations of the UserNameServer probe

The broker probe checks the UserNameServer to see if the bipservice process is still running.