In a WebSphere clustered environment there are usually multiple IHS(IBM derivative of Apache) servers set up to spray requests across a couple of Websphere Application Servers. This architecture assumes that the application static content(image files, html etc.) is deployed to the IHS boxes i.e it is not contained in the EAR file that is deployed on WebSphere. However the default WebSphere installation sets up WebSphere to serve static content and in this scenario IHS forwards all requests to WebSphere i.e it's redundant. In fact you can un-install IHS and configure WebSphere to listen on port 80. However IHS is a much more efficient file server and in a production environment it recommended that IHS serve static data. Hence if you bundle everything into the EAR file this won't happen and performance will suffer. I realize that the J2EE spec recommends that EAR files are self contained but if you want performance then separate static data.
subject: Tip - WebSphere Clustered Environment - IHS Static Data.