Disk File Optimizer (DFO)

Disk File Optimizer (DFO)

The Disk File Optimizer software is an OpenVMS utility designed to reduce file fragmentation on a storage device while that device remains on line to other users. The utility does not prevent users from accessing their files while it is running. If a user tries to access a file while it is being defragmented, the defragmentation process releases the file to the user and moves on to other files that require defragmentation. The file defragmentation utility is compatible with any Files–11 structure level 2 (ODS–2) formatted device including single volumes, bound volume sets, stripe sets, and shadow sets. The file defragmentation utility is also compatible with ODS-5 formatted device on OpenVMS Alpha 7.3 and above.


  • Safe defragmentation
  • Works online
  • Unattended operation
  • VMS Cluster compatibility
  • Automatic scheduling
  • Defragmentation Levels

Latest Version



Integrity: per active socket.
Alpha: ALPHA-LP.