Some situations might cause interruptions to file system availability on one or more systems. Following is a list of some of the most common causes. It is not meant to be an exhaustive list.

• Loss of the file system owner. If the file system owner leaves the shared file system group (through system failure, soft shutdown, VARY, XCF, OFFLINE, or some other means), an attempt might be made to establish another file system owner if requested by the AUTOMOVE specification of the mount. If a new file system owner cannot be established, the file system will become unowned. It will be unavailable until the original owner can reclaim it, or until another owner is established through subsequent automated recovery actions performed by shared file system.
• PFS termination. If a PFS terminates on one system, it can affect file system availability on other systems. If a PFS terminates on one system, any file systems of that type that are owned by other systems are not affected. File systems of that type are moved to new owners whenever possible if they are owned by the system where the PFS is terminating and if they can be automoved. These file systems remain accessible to other systems. If they cannot be moved to new owners, they are unmounted across the sysplex. It might not be possible to move a file system due to a lack of connectivity from other systems, or if the file system containing the mount point for the file system needed to be moved but could not be.
• VARY volume,OFFLINE. When the volume for a file system is varied offline, it will make that file system inaccessible to that system. However, if the volume is online to other systems, it might still be accessible to those systems and to other systems via cross-system messaging. This would be the case for sysplex-aware file systems for read/write or read-only access. Unlike loss of the file system owner, varying a file system volume offline will not result in any attempt by the system to restore accessibility to systems on which it is lost.