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Maximum Directory Size?

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The Question is:

When you are setting up a new Directory under Open VMS, can you tell me whats
 the largest number of files as a general rule that should be on a given
 directory? I am looking at a new directory which will have between 12-15k
 files. Should it be spread out
into different directories or is system's performance OK with that many files
 on one directory?
Thanks, John

The Answer is :

  The question is one of directory size, the frequency of insertions
  and removals and searches, and particularly the patterns of the
  insertions and removals.  The maximum directory size is limited by
  the free contiguous disk space.  Directory cache processing was
  overhauled with V7.2, so the older 128 block directory size limit
  no longer holds -- this is briefly discussed in the OpenVMS FAQ.
  The OpenVMS Wizard would tend to split up that number of files if for
  no other reason than the length of the directory displays.  Additionally,
  the effort involved in recovering or restoring directories of this size
  could easily be disruptive to your application environment -- archiving
  smaller groups of files based on creation or access date is easier, for
  instance, than sorting through and archiving a mixture of active and
  inactive files.
  The OpenVMS Wizard has a single OpenVMS mail directory containing well
  over 12,000 individual mail message files.  The directory file itself
  requires about two thousand blocks.  This works nicely, and with no
  particular performance consequences or degradation noted.  The system
  is an older workstation system with comparatively slow disks, running
  OpenVMS Alpha V7.3-1.
  For a more specific answer, you will have to prototype your operations.

answer written or last revised on ( 27-JAN-2003 )

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