z/OS Distributed File Service zFS Administration
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z/OS File System overview

z/OS Distributed File Service zFS Administration

The z/OS® Distributed File Service z/OS File System (zFS) is a z/OS UNIX System Services (z/OS UNIX) file system that can be used in addition to the hierarchical file system (HFS). zFS file systems contain files and directories that can be accessed with z/OS UNIX application programming interfaces (APIs). These file systems can support access control lists (ACLs). zFS file systems can be mounted into the z/OS UNIX hierarchy along with other local (or remote) file system types (for example, HFS, TFS, AUTOMNT, and NFS). For more information about ACLs, see z/OS UNIX System Services Planning.

zFS can be used for all levels of the z/OS UNIX System Services hierarchy (including the root file system). Because zFS has higher performance characteristics than HFS and is the strategic file system, HFS might not be supported in any future releases, which will cause you to migrate the remaining HFS file systems to zFS.

zFS can run sysplex-aware for read/write mounted file systems and for read-only mounted file systems. For more information, see Specifying zFS file systems as sysplex-aware, Terminology and concepts, and Using zFS in a shared file system environment.

Beginning with z/OS V1R13, zFS has enhanced its sysplex-aware support. For many file operations, zFS can now directly access zFS read/write mounted file systems in a shared file system environment from zFS client systems. In z/OS V1R13 and later releases, when zFS runs in a shared file system environment, zFS always runs sysplex-aware on a file system basis (sysplex=filesys). See zFS enhanced sysplex-aware support for more information.

zFS and HFS can both participate in a shared sysplex. However, only zFS supports security labels. Therefore, in a multilevel-secure environment, you must use zFS file systems instead of HFS file systems. See z/OS Planning for Multilevel Security and the Common Criteria for more information about multilevel security and migrating your HFS version root to a zFS version root with security labels.

  1. Beginning with z/OS V2R1, zFS no longer supports multi-file system aggregates. If you have data stored in zFS multi-file system aggregates, copy that data from the zFS multi-file system aggregate file systems into zFS compatibility mode aggregates. Because zFS multi-file system aggregates cannot be mounted in z/OS V2R1, you must copy the data from any file systems contained in multi-file system aggregates into zFS compatibility mode file systems using a non-shared file system environment on a system running a release prior to z/OS V2R1.
  2. Beginning with z/OS V2R1, zFS no longer supports clones. If you have read-only clone (.bak) file systems, you should delete them using the zfsadm delete command.

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