Abstract

In order to decrease the overall cost of storing large amounts of data, systems have been developed that use a hierarchy of storage devices from fast local disks to archival off-line storage. Such storage devices may be managed in a hierarchy where data that is accessed only infrequently can be moved to archival storage. The present invention relies on a tight integration of a hierarchical storage manager into the I/O system so that remotely stored attributes can be identified and tracked internally to the I/O system just like any other attributes. Implementations of the present invention may rely on a layered driver model where lower level drivers detect the existence of files with remotely stored attributes and then transfer control for processing I/O requests involving files with remotely stored attributes to higher level drivers. The higher level drivers then assume control to finish processing the I/O request.