Abstract: A filesystem-aware storage system locates and analyzes host filesystem data structures in order to determine storage usage of the host filesystem. To this end, the storage system might locate an operating system partition, parse the operating system partion to locate its data structures, and parse the operating system data structures to locate the host filesystem data structures. The storage system manages data storage based on the storage usage of the host file system. The storage system can use the storage usage information to identify storage areas that are no longer being used by the host filesystem and reclaim those areas for additional data storage capacity. Also, the storage system can identify the types of data stored by the host filesystem and manage data storage based on the data types, such as selecting a storage layout and/or an encoding scheme for the data based on the data type.

Abstract: A dynamically expandable and contractible fault-tolerant storage system employs a virtual hot spare that is created from unused storage capacity across a plurality of storage devices. This unused storage capacity is available if and when a storage device fails for storage of data recovered from the remaining storage device(s). On an ongoing basis, the storage system may determine the amount of unused storage capacity that would be required for the virtual hot spare (e.g., based on the number of storage devices, the capacities of the various storage devices, the amount of data stored, and the manner in which the data is stored) and generate a signal if additional storage capacity is needed for a virtual hot spare.

Abstract: A dynamically upgradeable fault-tolerant storage system permits a storage device to be replaced with a larger storage device. Data stored redundantly across multiple storage devices is reproduced on the replacement device, and the additional storage space on the replacement device is made available for redundantly storing additional data.