zSeries File System

The zSeries File System (zFS) is a 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 the z/OS hierarchical file system file Application Programming Interfaces (APIs). 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, NFS, etc.).

zFS does not replace HFS, rather zFS is complimentary to HFS. HFS is still required for z/OS installation and the root file system must be HFS.