A partition in eDirectory is a logical group of objects in an eDirectory tree. Partitioning allows you to manage the tree by taking part of the directory from one server and putting it on another server. If you have slow or unreliable WAN links or if your directory has so many objects that the server is overwhelmed and access is slow, you should consider partitioning the directory.
Each directory partition consists of a set of container objects, all the objects contained in them, and data about those objects. eDirectory partitions don’t include any information about the file system or its directories and files. Partitions are named by their topmost container.
For a complete discussion of partitions, see Managing Partitions and Replicas.
A domain in DSfW is a security boundary that is similar to a partition in eDirectory. The domain also forms the administrative and security boundary for a logical group of network resources such as users or computers. Typically, a domain resides in a localized geographic location; however, this might not always be the case. Domains are commonly used to divide global areas of an organization and its functional units.