Patent ID: 8825591

Claim:
A system, comprising: a processor; and a memory comprising program instructions, wherein the program instructions are executable by the processor to implement file system software configured to: establish and manage a file system on a plurality of storage devices; provide access to files in the file system to one or more applications, wherein each file comprises one or more file parts; track subfile-level statistics for a file in the file system on a first storage device of the plurality of storage devices; determine from the subfile-level statistics for the file one or more parts of the file that can be migrated from the first storage device, wherein, to determine from the subfile-level statistics for the file one or more parts of the file that can be migrated from the first storage device, the file system software is further configured to: determine the one or more parts of the file are frequently-accessed parts of the file that can be migrated to the second storage device; and determine the other one or more parts of the file are infrequently-accessed parts of the file; and migrate the one or more parts of the file to a second storage device of the plurality of storage devices; wherein one or more other parts of the file remain on the first storage device; wherein the migrated one or more parts of the file remain online within the file system.