Chapter 2. Overview of WebSphere Application Server V5 33
requests among Application Server instances that are running on multiple
physical machines.
Clusters
Clusters are sets of servers that are managed together and participate in
workload management. The servers that are members of a cluster can be on
different host machines, as opposed to the servers that are part of the same
node and must be located on the same host machine.
A cell can have no clusters, one cluster, or multiple clusters. Servers that belong
to a cluster are members of that cluster set and must all have identical
application components deployed on them. Other than the applications
configured to run on them, cluster members do not have to share any other
configuration data. ...