US Patent 11061868 Persistent cache layer to tier data to cloud storage

Implementations are provided herein for having at least two data streams associated with each file in a file system. The first, a cache overlay layer, can store additional state information on a per block basis that details whether each individual block of file data within the cache overlay layer is clean, dirty, or indicates that a write back to the storage layer is in progress. The second, a storage layer, can be a use case defined repository that can transform data using data augmentation methods as a part of tiering data to external repositories. File system operations directed to the cache overlay layer can be processed asynchronously from file system operations directed to the storage layer.