DFSMS/VM Overview

DFSMS/VM is a feature of z/VM designed to (1) manage files in Shared File System (SFS) file pools, (2) help you move CMS minidisks between like and unlike direct access storage devices (DASD) quickly and efficiently, and (3) provide command and Callable Services Library (CSL) interfaces to removable media library support.

Figure 1 shows the four major functional components of DFSMS/VM:
Figure 1. DFSMS/VM Major Components
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  • User interface consists of:
    • Interactive Storage Management Facility (ISMF), which offers a set of menus, data entry panels, and list panels that run on the user’s virtual machine. Through ISMF, you can select applications to:
      • Perform storage management functions against the file and minidisk lists
      • Create file, minidisk, and management class lists based on your criteria
      • Define management classes
      • Edit and test automatic class selection (ACS) routines
      • Define the installation’s space management policies in DFSMS configurations
      • Activate DFSMS/VM configurations.
    • DFSMS module, which provides a command interface to most minidisk and storage management functions
    • DFSMSRM module, which provides a command interface to removable media services functions
    • A set of CSL-routine programming interfaces to removable media services functions.
  • Minidisk management provides:
    • A high-performance data mover for copying CMS-formatted minidisks between like and unlike DASD
    • The capability to do an integrity-evaluation of CMS minidisks
    • The capability to perform the move and integrity-evaluation operations against a list of minidisks.
  • Space management provides:
    • Automatic assignment of management classes to SFS files and directories
    • Automatic migration (with compaction) or erasure of selected SFS files based on management class policies
    • Migration to ML1 and ML2 (lower cost tape and/or dasd)
    • Automatic recall of migrated files upon reference
    • Command-initiated migration and recall of files.
  • Removable media services (RMS) provides:
    • Support of the IBM 3495 Tape Library Dataserver to extend automated mount support and other library capabilities to z/VM users and guests, as well as tape management applications.