US Patent 9116904 File system operation on multi-tiered volume

A file system that operates on an underlying volume that has multiple tiers, each tier including a particular trait set. Upon creating or otherwise identifying a file system namespace (such as a directory or file) that is in a volume or that is to be included within the volume, a storage trait set to be applied corresponding to the file system namespace is identified. Then, the storage trait set is compared against the trait sets for the multiple tiers to identify a tier into which to store the file system namespace. The file system namespace is then caused to be stored within the identified tier. Thus, the file system is provided with a volume that has multiple tiers (each having different trait sets) to choose from in storing files.