Oracle Coherence Monitor User Guide

Oracle Coherence Monitor

User Guide

JMX Connection Choices
The RTView OC Monitor application collects capacity and performance metrics from an operational Coherence Cluster using standard JMX protocols. These metrics are made available to developers and support personnel for analysis and alerting using RTView desktop applications, Web browser clients, or passively via event-triggered alerts.

There are several modes by which the OC Monitor may connect to a Coherence cluster using JMX. With RTView, users have a choice as to which mode to use, either of which may be relevant or appropriate depending on the monitoring requirement. This is especially important in a situation where users are called on to monitor and manage multiple disparate clusters.

Connection to Cluster using JMX Remote Port or RMI URL
In this mode, the OC Monitor makes a connection to a remote JMX port or RMI URL exposed by a node in the cluster that has been configured as a Coherence “management” node on startup. This node must also have defined its JMX remote port or RMI URL using standard JMX configuration properties and may include a requirement for secure user authentication.

Once connected, the OC Monitor begins querying all (or a subset) of the MBeans from the Coherence management node at a regular interval.

NOTE: The management node may exist on the same machine as the OC Monitor; the “remote” designation simply means that the JMX connection is made to MBeans instanced in a separate process from the OC Monitor.

The information required for the OC Monitor to connect in this manner is minimal, only the host and port, or RMI URL. Typically, this makes it quick and easy to begin monitoring a cluster, a particular advantage in development environments where clusters come and go on a regular basis. There is no need to configure, then start and stop an agent in order to monitor the cluster.

Another advantage of remote JMX collection is that you do not have to install anything in the cluster or in a production environment – often the cluster itself is running behind a firewall and the monitor does not have easy access to the data. As long as a management node in the cluster exposes JMX MBeans, the connection process can be completely hands off.

A third advantage to this mode is that the OC Monitor makes no Coherence API calls, meaning that there is a next-to-zero chance of corrupting or crashing the cluster through improper configuration. The rate at which the JMX data are queried can be easily tuned so as to put a minimal monitoring load on the management node in the cluster and on the cluster itself.

Additionally, by having a Coherence management node in the cluster, it can act as backup in case the monitoring system itself goes down.

One disadvantage of the remote JMX connection is that its performance can degrade as the number of monitoring MBeans grows with the complexity of the cluster. A simple measure of cluster complexity is the product of number of nodes (N) times the number of caches supported by the cluster (C). Practical experience has shown that a cluster consisting of 150 nodes and 10 caches (N * C = 1500) can be adequately monitored using the remote JMX connection. Clusters larger than this can benefit from the direct connection mode described in the next section.

Direct Connection to Cluster as a Coherence Management Node
In this mode, the OC Monitor itself joins the cluster and establishes itself as a management node. As a management node, it is configured with local data storage disabled so that it does not store any cache data and serves only as a monitoring node. In this role, it creates the JMX MBean server in-process and collects JMX monitoring data from other Coherence node using fast internal Coherence protocols.

The primary advantage for this mode speed. In practice, this performance improvement can range from 2 to 10 times faster, depending a number of factors, in particular the network configuration environment.

However, there are tradeoffs. In order to use the direct connection mode, one must have access to all of the important cluster configuration parameters that are used by other nodes in the cluster. These include the Coherence override file, or specific settings like cluster name, well-known address, multicast ports, and Coherence mode. Having limited access to this information can make the configuration process time-consuming.

RTView contains components licensed under the Apache License Version 2.0.

JMS, JMX and Java are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries. They are mentioned in this document for identification purposes only.

SL, SL-GMS, GMS, RTView, SL Corporation, and the SL logo are trademarks or registered trademarks of Sherrill-Lubinski Corporation in the United States and other countries. Copyright © 1998-2011 Sherrill-Lubinski Corporation. All Rights Reserved.