Patent ID: 7552131

Claim:
A method of determining whether to retain data within at least one storage device, said method comprising: storing data items in at least one storage device; maintaining access statistics for each of said data items; maintaining an age of each of said data items; maintaining an administrator-defined importance value of each of said data items; and calculating a retention value for each of said data items based on said access statistics for each of said data items, said age of each of said data items, and said administrator-defined importance value of each of said data items; wherein said calculating of said retention value comprises creating clusters of data points, wherein each of said data points comprise a function of data item age and data item number of accesses; and wherein said calculating of said retention value further comprises mapping said clusters into linear functions; wherein said mapping of said clusters into said linear functions comprises creating said linear functions such that said linear functions comprise slopes that are inversely proportional to densities of said clusters; wherein said mapping of said clusters into said linear functions comprises creating said linear functions such that coordinate ranges of said linear functions correspond to diameters of said clusters; wherein said calculating of said retention value further comprises combining said linear functions with said administrator-defined importance value of each of said data items in an adjustable weighted function; and wherein said removing data items that have a retention value below a predetermined value from said storage device.