Storage virtualization and storage management to provide higher level storage services

In a storage server on a storage area network, a media unit manager manages disk space in a manner transparent to the host computers (106). The media manager (120) uses media units corresponding to the physical storage devices (104) on the storage area network to build higher level media units. The higher level media units can have attributes of being sliced concatenated, mirrored, striped, etc. Thus the host computers (106) need not be aware of the specific physical storage devices themselves, reducing the management and reconfiguration burden on the host computers (106) when storage devices (104) are added to or removed from the storage area network.