Sun Java System Application Server 9.1 Deployment Planning Guide

Management Domains

An HADB management domain is a set of hosts, each of which has a management agent running on the same port number. The hosts in a domain can contain one or more HADB database instances. A management domain is defined by the common port number the agents use and an identifier (called a domainkey) generated when you create or the domain or add an agent to it. The domainkey provides a unique identifier for the domain, crucial since management agents communicate using multicast. You can set up an HADB management domain to match with an Application Server domain.

Having multiple database instances in one domain can be useful in a development environment, since it enables different developer groups to use their own database instance. In some cases, it may also be useful in production environments.

All agents belonging to a domain coordinate their management operations. When you change the database configuration through an hadbm command, all agents will change the configuration accordingly. You cannot stop or restart a node unless the management agent on the node’s host is running. However, you can execute hadbm commands that read HADB state or configuration variable values even if some agents are not available.

Use the following management client commands to work with management domains: