Computer data file system with consistency groups as basic file system objects

A computer has a secondary storage device with a filesystem for persistent storage of application data, the filesystem having filesystem objects including files, directories, and group objects such as consistency groups. The group objects specify respective groups of the filesystem objects on which certain filesystem group operations act as a unit. The filesystem also has filesystem routines for performing filesystem operations including single-object operations and group operations. A single-object operation acts upon a specified user file or directory independently (e.g., opening or reading from a file), while a group operation acts upon a respective set of filesystem objects grouped together by a specified group object.