You can assign a particular directory service for a particular virtual server. When you do so, the directory service you choose is logged under the USERDB element of the corresponding VS (virtual server) element in the server.xml file. The rights and permissions associated with this directory service is later used by the server to evaluate and enforce access control rules.
To assign a directory service to a virtual server, perform the following steps
From the Virtual Server Manager choose the Settings tab.
A listing of the virtual server settings is displayed.
Click the Edit link next to Directory Services.
The Pick Directory Services for Virtual Server page is launched in a new window.
Choose a directory service and click OK.
Save and apply changes.
The directory service you choose for a particular virtual server is not shared across other virtual servers. Access control files, on the other hand, are shared across virtual servers.