152 Achieving the Highest Levels of Parallel Sysplex Availability
– SYSNAME is a new parameter on the ROOT and MOUNT statements that specifies
the particular system on which a mount should be performed. The system will then
become the initial owner of the file system mounted. The default is the current system.
– AUTOMOVE, NOAUTOMOVE, and UNMOUNT are new parameters on the ROOT and
MOUNT statements used to decide what action is to occur when the system that owns
the file system goes down. The default is AUTOMOVE. Refer to 3.15.2, “Automove” on
Automount policy management
Prior to shared HFS, automount policies could be system specific with a sysplex. With
shared HFS, all mounted file systems area available to all systems participating in shared
HFS; therefore the policies should be identical in the /etc/auto.master associate map files
maintained by each system.
Automove is a feature of shared HFS that determines how file system ownership is to be
managed if the owning system goes down. Valid options are:
AUTOMOVE specifies that ownership of the file system automatically moves to another
NOAUTOMOVE specifies that ownership of the file system is not moved and, as a result,
the file system becomes inaccessible.
Prior to z/OS 1.4, the relocation of file system ownership was random and any of the other
shared HFS participating systems could become the new owner. z/OS 1.4 has provided new
parameters on the MOUNT statement to give an installation more control over this process:
AUTOMOVE(INCLUDE,sysname1,sysname2,...) may be used to specify a prioritized list
of systems where the file system ownership may be moved.
AUTOMOVE(EXCLUDE,sysname1,sysname2,...) may be used to specify a list of systems
where the file system ownership may not be moved.
UNMOUNT specifies that the file system should be unmounted, including any file systems
mounted within its subtree.
It is recommended that the sysplex root and version HFS are designated as AUTOMOVE to
allow another system to take ownership of these file systems when the owning system goes
The system-specific HFS, and other HFSs containing file systems that are managed on a
system-specific basis (/dev, /tmp, /var, /etc) should be designated as NOAUTOMOVE to
prevent change in ownership.
It is not advisable to mount AUTOMOVE file systems within NOAUTOMOVE file systems, as
the file system concerned will not be recovered after a system failure until the failing system is
Specify NOAUTOMOVE for file systems that are mostly used by DFS™ clients. A file system
can only be exported by the DFS server on the system that owns the file system. Once a file
system has been exported by DFS it cannot be moved until it has been un-exported from
When a system is removed from a sysplex, there is a window of time during which any file
systems it owned will become inaccessible to other systems. This window occurs while other