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 set of file systems and maintaining a directory while providing the directory is capable of residing in more than one sub-file system within the hierarchical file system. If available space in a first sub-file system is below a threshold, the system identifies a second sub-file system with available space above the threshold, wherein the first sub-file system contains a first portion of the directory. If a second portion of the directory exists in the second sub-file system, the system creates or expands a file in the second portion of the directory, otherwise the system first creates the second portion of the directory in the second sub-file system and then creates a link from the first portion of the directory to the second portion of the directory.