Syntax:

           /[NO]REPLACE

  Use /REPLACE to delete an existing DMU record definition and insert a
  new definition in its place.  Access control lists remain unchanged, as
  do history lists, unless you specify /AUDIT to create entries recording
  the replacement.

  /NOREPLACE is the default.  If you try to compile a source file for an
  existing DMU record definition without specifying /REPLACE or /VERSION,
  the CDDL aborts the compilation and issues an error message.

  You cannot specify /VERSION or /[NO]ACL with /REPLACE.