Shared File System

The Shared File System (SFS) is an extension of the CMS file system that offers additional file management and file sharing functions:
  • Files are stored in file pools.
  • A user can be given an amount of file space in a file pool.
  • The files in a file space are organized in directories.
  • A file can be placed in more than one directory.
  • Users can grant each other authorities on files or directories.
  • Multiple users can have concurrent access to the same file or directory.
  • Locks on files and directories ensure data integrity among multiple users.
  • Files and directories can be shared with users on other systems.

A file pool is a collection of minidisks assigned to a single virtual machine called a file pool server machine. Because the minidisks in the file pool are shared by many users, using SFS can save DASD space. Certain SFS directories can be placed into VM data spaces, providing an additional DASD savings. Using VM data spaces might also provide a performance improvement.

For more information, see:

For information about how DFSMS/VM can provide storage management functions for file pools, see Data Facility Storage Management Subsystem for VM (DFSMS/VM).