Storage area network methods and apparatus using event notifications with data

An storage area network (SAN) has a manager digital data processor that includes a first element that maintains a first representation of the SAN and a second element that maintains a second representation of the SAN. The first element generates notifications of events in the SAN, e.g., addition or removal of components or relationships between components, and includes with them data pertaining to the event. The second element responds to such notifications and data by updating the second representation. That data is preferably sufficient for the second element to update the second representation without further reference to information contained in the representation.