Administering aggregates

The z/OS Distributed File Service (DFS) zSeries File System (zFS) is a z/OS UNIX file system that can be used in addition to the Hierarchical File System (HFS).

zFS provides significant performance gains in accessing files approaching 8 KB in size that are frequently accessed and updated. For smaller files, the access performance with zFS is equivalent to HFS. zFS provides a reduced exposure to loss of updates by writing data blocks asynchronously and not waiting for a sync interval.

zFS is a physical file system (PFS) that is started by UNIX System Services during the IPL. A physical file system is the part of the operating system that manages the actual storage and manipulation of data on a storage medium.

zFS logs metadata updates. If system failure occurs, zFS replays the log when the system is operational again to ensure that the file system is consistent.

Note

An aggregate is a VSAM linear data set (LDS) that contains one or more zFS file systems. There are two types of aggregates:

  •  HFS compatibility mode (contains 1 zFS file system)
  •  Multiple file system (contains 1 or more zFS file systems)
    (z/OS V1R13 is the last version where zFS supported multi-file system aggregates.)

 

This section contains the following topics:

Related topic

Controlling-UNIX-System-Services





 

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