The IBM WebSphere Application Server product uses the following definitions:
Administrative domain. The logical space in which the configurations for various objects in the WebSphere environment reside. Inside one administrative domain you start with an application server. This is the default installation.
Server group. A server group is a template for creating additional, nearly identical copies of an application server configuration. (This is the equivalent of BEA’s cluster.)
Clones. A copy of the server group, on the same machine or on different machines. Clones are the equivalent of BEA’s managed servers.
See the IBM WebSphere Application Server documentation for more information:
http://www-306.ibm.com/software/webservers/appserv
WebSphere Advanced Server provides a more robust approach to clustering because it includes a database. In Advanced Server, all servers use the database for the configuration information. You can use the WebSphere administration console, a Swing Java application, or the command-line utilities XMLConfig and wscpthen to manage the servers.