Patent ID: 8468176

Claim:
A method for storing data from a host in an extended data storage system comprising a first data storage of high speed and an extended data storage of lower speed, comprising the steps of: establishing in said first high speed data storage a first level of metadata with respect to data from said host, said first level of metadata identifying said data for access by said host; storing said data from said host in said extended data storage and storing a copy of said first level of metadata in said extended data storage; establishing a second level of metadata at least describing said data as stored in said extended lower speed data storage and stored in the form of a header, said second level of metadata associated with said first level of metadata for said stored data via a pointer; making said first level of metadata accessible to said host at said first high speed data storage; making direct access to said second level of metadata unavailable to said host; said storage system using said pointer to access and extract said second level of metadata; and said storage system using said extracted second level of metadata to retrieve said data from said extended data storage and using said first level of metadata to send said data to said host.