text: Figure 10-1 Easy Tier 
  
  Easy Tier monitors the I/O activity and latency of the extents on all Easy Tier enabled storage 
  pools. Based on the performance log, it creates an extent migration plan and*promotes*
  (moves) high activity or hot extents to a higher disk tier within the same storage pool. It also 
  *demotes*extents whose activity dropped off, or cooled, by moving them from a higher disk tier 
  MDisk back to a lower tier MDisk. 