One embodiment provides a method for storage management in a hierarchical file system. The method includes tracking directories for sub-file systems of the hierarchical file system. A request for creation of an additional directory in the hierarchical file system is received. In response to the request, the additional directory is created in a sub-file system of the hierarchical file system while providing that each directory resides in only one sub-file system. If the additional directory is a child directory, the additional directory is created in the sub-file system containing the parent directory of the child directory.