Title:        Hedwig JMX
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h1. JMX

Apache Hedwig has extensive support for JMX, which allows viewing and managing a hedwig cluster.

This document assumes that you have basic knowledge of JMX. See "Sun JMX Technology":http://java.sun.com/javase/technologies/core/mntr-mgmt/javamanagement/ page to get started with JMX.

See the "JMX Management Guide":http://java.sun.com/javase/6/docs/technotes/guides/management/agent.html for details on setting up local and remote management of VM instances. By default the included __hedwig__ script supports only local management - review the linked document to enable support for remote management (beyond the scope of this document).

__Hub Server__ is a JMX manageable server, which registers the proper MBeans during initialization to support JMX monitoring and management of the instance.

h1. Hub Server MBean Reference

This table details JMX for a hub server.

| _.MBean | _.MBean Object Name | _.Description |
| PubSubServer | PubSubServer | Represents a hub server. It is the root MBean for hub server, which includes statistics for a hub server. E.g. number packets sent/received/redirected, and statistics for pub/sub/unsub/consume operations. |
| NettyHandlers | NettyHandler | Provide statistics for netty handlers. Currently it just returns number of subscription channels established to a hub server. |
| ReadAheadCache | ReadAheadCache | Provide read ahead cache statistics. |