Patent attributes
A data storage system is disclosed, including: a first storage device of a first storage device type, a second storage device of a second storage device type, and a processor configured to implement a hybrid file system configured to store each of a plurality of data values in at least a corresponding primary location, which for a given data value may be in either the first storage device or the second storage device; wherein the hybrid file system is configured to use a first access approach optimized based on a first access attribute of the first storage device type to interact with the first storage device and a second access approach optimized based on a second access attribute of the second storage device type to interact with the second storage device. Reading data is disclosed, including: determining that a storage location on a first tier storage from which a requested data was written back to a second tier storage has not been reclaimed by a garbage collection associated with the first tier storage, and retrieving the data from the storage location on the first tier storage.