WebSphere® environment variables with server and port references should be defined at the server level. These variables have values beginning with corbaloc:iiop.
WebSphere environment variables that do not have server and port references can be at the cluster, node, or cell scope because they are common across servers. These variables contain reference and schema names. They can be at the cell or cluster scope to minimize configuration.
Configure WebSphere artifacts that reference a particular machine's configuration at either the node (machine) or server (runtime code on the machine) level. For example, a JDBC provider uses a location in a machine file system that can vary from node to node.
A WebSphere artifact must be defined at the same scope or lower scope than all of the artifacts it uses. For example, data sources using a JDBC provider must be at the same scope as the provider.