Mapping an application to application server(s) or web server(s) lets you control what server(s) will be able to produce the application.
In this example, the Beta application is mapped to server01 in node02 in cell was1Cell01.
This is a very simple configuration, where the application is running on a single application server.
One web server / one application server
In this example, the Beta application is running on both server01 (the application server) and IHS (the web server).
This is a fairly common for applications that are not mission critical. In this example, the web server is probably configured to produce the applications running on the JVM.
One web server / two application servers
In this example, the Beta application is running on cluster 1 (two application servers) and IHS (one web server).
This introduces some high availability capabilities. If application server "server 1" goes down, the application will still be able to be produces by application server "server 2".
This can also be done via the wsadmin command.
./wsadmin.sh -user your_username -password your_password -c "AdminApp.edit('your_ear', '[ -MapModulesToServers [[ your_app Example.war,WEB-INF/web.xml WebSphere:cell=your_cell,cluster=your_cluster+WebSphere:cell=your_cell,node=your_node-node,server=your_web_server ]]]' )" ./wsadmin.sh -user your_username -password your_password -c "AdminConfig.save()"