Storage Foundation Cluster File System High Availability is based on Veritas File System (VxFS).
Most of the major features of VxFS local file systems are available on cluster file systems, including the following features:
Online administration that allows file systems to be extended and defragmented while they are in use
Every VxFS manual page has a section on "Storage Foundation Cluster File System Issues" with information on whether the command functions on a cluster-mounted file system and indicates any difference in behavior from local mounted file systems.