A reliable utility to quickly move, copy and backup data.

Data Set Services (DFSMSdss™) is a component of DFSMS™ (Data Facility Storage Management Subsystem), and is used to:

  • Move and replicate data—DFSMSdss offers powerful, user-friendly functions that let you move or copy data between volumes of like and unlike device types. It can also copy data that has been backed up.
  • Manage storage space efficiently—DFSMSdss can increase performance by reducing or eliminating DASD free-space fragmentation.
  • Backup and recover data—DFSMSdss provides you with host system backup and recovery functions at both the data set and volume levels with encryption capabilities. It also includes an enhanced Stand-alone Restore Program that lets you restore vital system packs during disaster recovery - without a host operating system.
  • Convert data sets and volumes—DFSMSdss can convert your data sets and volumes to system-managed storage, or return your data to a non-system-managed state as part of a recovery procedure - all without data movement


FlashCopy provides a fast data duplication capability. This option helps eliminate the need to stop applications for extended periods of time in order to perform backups and restores. FlashCopy is automatically initiated by DFSMSdss on IBM Enterprise Storage Servers (ESS) with the FlashCopy feature. With DFSMSdss you can exploit advanced Flashcopy functions like Incremental FlashCopy, Space Efficient FlashCopy, Fast Reverse Restore, and Remote Pair FlashCopy.

Concurrent Copy (CC)

Concurrent Copy (CC) is both an extended function in cached IBM Storage Controls and a component of DFSMSdss. CC enables you to copy or dump data while applications are updating the data. Both IMS/ESA and DB2 can use CC for their backups.

Virtual Concurrent Copy (VCC)

Virtual Concurrent Copy is an extended function that performs Concurrent Copy utilizing FlashCopy. In VCC data is flash-copied from the source location to an intermediate location and then gradually copied to the target location using normal I/O methods.


SnapShot is a function that allows you to make a very quick copy of a set of tracks (an entire volume, a data set, or just a random set of tracks). The copy operation is completed with only a few I/Os to the device. SnapShot supports zSeries attached (CKD) devices.

DFSMSdss Stand-Alone Services

The stand-alone restore function is a single-purpose program designed to allow the system programmer to restore vital system packs during disaster recovery without needing to rely on an OS/390 or z/OS environment. With the Customized Offering Driver (5751-COD) shipped on DVD, it is no longer required to have a tape drive to create a z/OS driving system.

Product highlights

  • This high-speed component of DFSMS (Data Facility Storage Management Subsystem) is a fast, efficient data mover that is particularly valuable to customers moving many data sets from old to new disk subsystems.
  • A new "Compatible Disk Layout" for volumes under Linux on z/OS allows DFSMSdss to perform copy, dump and restore from the z/OS operating system.
  • Data Set Services (DFSMSdss™) is used to move data from disk to disk (copy) or disk to tape (dump) very quickly and efficiently. It performs both logical dumps ( to copy data) and physical dumps ( to copy track images).
  • DFSMSdss is an external interface to FlashCopy, Concurrent Copy, Virtual Concurrent Copy, and SnapShot. It is also the file manager for DFSMShsm and fully supports ABARS.

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