Patent attributes
System and method for implementing a file system across different storage classes in a storage system. Embodiments may define multiple classes of storage and automatically and transparently migrate data in the storage classes within the same file system to meet the usage needs of the business. Embodiments may transparently adapt the cost of storage to the usage patterns of data on the storage, thereby reducing the amount that customers need to spend for their storage. In embodiments, storage devices may be classified into different classes of storage to implement a multi-class file system. Embodiments may provide a multi-class storage mechanism for managing and implementing user-defined policies for assigning and migrating data within the multi-class file system. The multi-class storage mechanism may determine where to initially place data, and may transparently migrate data to other storage classes according to the policies. Migrated data remains online within the file system.