Function

unmount invokes the unmount callable service to unmount a file system; that is, it removes a file system from the file hierarchy.

Requirement: The caller must have unmount authorities to unmount a file system. See the section on mount authority in z/OS UNIX System Services Planning.

Parameters

name

The name of the file system to be unmounted, specified as the name of an HFS data set. You must specify the HFS data set name as a fully qualified name in uppercase letters. Do not enclose the data set name in single quotes.

flags

The unmount options, expressed as a numeric value. You can specify a numeric value (see REXX predefined variables) or the predefined variable beginning with MTM_ used to derive the appropriate numeric value:

Variable	Description
MTM_DRAIN	An unmount drain request. All uses of the file system are normally ended before the file system is unmounted.
MTM_FORCE	An unmount force request. The file system is unmounted immediately, forcing any users of the named file system to fail. All data changes made up to the time of the request are saved. If there is a problem saving data, the unmount continues and the data may be lost. So that data will not be lost, you must issue an unmount immediate request before an unmount force request.
MTM_IMMED	An unmount immediate request. The file system is unmounted immediately, forcing any users of the named file system to fail. All data changes made up to the time of the request are saved. If there is a problem saving data, the unmount request fails.
MTM_NORMAL	A normal unmount request. If no one is using the named file system, the unmount request is done. Otherwise, the request is rejected.
MTM_RESET	A reset unmount request. This stops a previous unmount drain request.
MTM_REMOUNT	Unmounts the file system, changes the mount mode, and remounts the file system. A read/write mount mode changes to read-only. A read-only mount mode changes to read/write.
MTM_SAMEMODE	Remounts the file system without changing the mount mode. This can be used to regain the use of a file system that has I/O errors.

Usage notes

1. A file system that has file systems mounted on it cannot be unmounted. Any child file systems must be unmounted first.
2. A reset request can stop only an unmount service drain request. There is no effect if it is issued when there is no umount request outstanding.