RMAN real usage of MAXSETSIZE, MAXPIECESIZE, FILESPERSET, SECTION SIZE, MAXOPENFILES

http://www.dbarj.com.br/en/2015/02/rman-real-usage-maxsetsize-maxpiecesize-filesperset-section-size-maxopenfiles/

http://oracleinaction.com/tune-rman-i/