Before the solid state disk (SSD) enhancements, you were required to specify an absolute value of the temperature when you used the ACCESSTEMP criteria and IOTEMP criteria in the SmartTier placement policies. However, arriving at such absolute numbers is difficult and requires you to experiment and observe data access patterns over a period of time. Moreover, over a period of time, you might have to change this value due to changing access patterns. As such, you might need to repeat the experiment. To ease constructing ACCESSTEMP and IOTEMP-based policies, a new criteria has been introduced: Average.

See Average I/O activity criteria.