sizingMode 
  Specifies how the provisioned SSD read cache is sized, as follows:
- Set to - NO_CACHEif you do not want to use an SSD read cache with your Intelligent-Tiering file system.
- Set to - USER_PROVISIONEDto specify the exact size of your SSD read cache.
- Set to - PROPORTIONAL_TO_THROUGHPUT_CAPACITYto have your SSD read cache automatically sized based on your throughput capacity.