ASM Cluster file systems are created on ASM volumes that are presented as disk devices. ASM volumes are constructed from ASM files that distribute segments of each ASM file across multiple disks configured within each disk group, for increased parallelism. ACFS supports a multiple storage device model where an individual ACFS file system may optionally span multiple device files. This facilitates the management of the physical storage devices independently from the ACFS directory hierarchy and thus enables file data management operations such as migration of files and file regions from one storage device to another, without impacting the file path or the ACFS name space. In addition, storage devices may be dynamically inserted and deleted from an ACFS file system, enabling dynamic resizing and transparent, on-line storage technology upgrades.