Oracle Coherence Monitor

User Guide

 

Configuring an OCM Agent
The OCM Agent is a method for acquiring JMX data from a Coherence cluster that reduces the occurrence of packet loss errors sometimes seen in large clusters. This method is especially useful for monitoring very large clusters containing many MBeans.

Normally, and by default, the Data Server acquires data from a Coherence cluster and supplies it to the OC Monitor.  The Data Server also aggregates and processes raw data into caches, and in the process creates large amounts of transient data. This extra overhead can cause long garbage collection pauses on a node in the cluster, and increase both communication delays and other garbage collection activity in the cluster.

The OCM Agent method employs an OCM Agent Data Server that joins the cluster and is dedicated solely to acquiring JMX data and forwarding it to the Data Server. The Data Server does not join the cluster and is dedicated solely to aggregating and processing raw data into caches. This configuration minimizes garbage collection, reducing the overhead for optimal monitoring.

To summarize the OCM Agent method process:

  1. The OC Monitor requests data from the Data Server.
  2. The Data Server forwards the request to the OC Monitor Agent Data Server.
  3. The OC Monitor Agent Data Server provides the data to the Data Server.
  4. The Data Server forwards the data to the OC Monitor.

The OCM Agent method entails an additional Java process (the OCM Agent) and an additional connection (between the Agent and the Data Server).

Enabling the OCM Agent

To enable the OCM Agent to gather data from the Coherence cluster, perform the following steps.

1.  Verify that all OC Monitor applications and the cluster are stopped. See Stopping the Monitor for details about stopping OC Monitor applications.

2.  Edit the cluster.properties file, located in the conf directory, to include the following property:

ocm.use_agent=true  

3. In the myocm directory, start the OC Monitor processes. For example:

startocm

This starts the OCM applications in the proper order. If you wish to not use the startocm script, you must start each application and in this order:

  • Agent

  • Data Server

  • Display Server

  • Historian

  

The OCM Agent is now configured to gather data from the Coherence cluster.

Disabling the OCM Agent

To disable the OCM Agent from gathering data from the Coherence cluster, perform the following steps.

1.  Verify that all OC Monitor applications and the cluster are stopped. See Stopping the Monitor for details about stopping OC Monitor applications.

2.  Edit the cluster.properties file, located in the conf directory, as follows:

ocm.use_agent=false  

3. In the myocm directory, start the OC Monitor processes. For example:

startocm.bat (Windows)

startocm.sh (UNIX/Linux)

NOTE: This starts the OCM applications in the proper order. If you do not wish to use the startocm script, you must start each application relevant to your OCM Agent deployment and in this order:

  • Data Server

  • Display Server

  • Historian

  

The OCM Agent is no longer configured to gather data from the Coherence cluster.

           
 

 

 

 


 

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