The Free On-line Dictionary of Computing (30 December 2018):

backup rotation

    Any system for re-using backup media,
   e.g. magnetic tape.  One extreme would be to use the same
   media for every backup (e.g. copy disk A to disk B), the other
   extreme would be to use new media every time.  The trade-off
   is between the cost of buying and storing media and the
   ability to restore any version of any file.  One example is
   the Grandfather, Father, Son (GFS) scheme.

   (2004-10-08)