MX series array, how does FAST manage data in a heterogeneous storage pool?

A.
It relocates more active data from tier 1 storage without users noticing the difference

B.
It relocates more active data to faster drives and less active data to slower drives

C.
It acts as an application accelerator and relocates LUNs based on performance

D.
It relocates LUNs from one tier to another to improve performance

Explanation:

Fast enables the customer to create storage pools with heterogeneous device classes (Flash, SAS, and NLSAS) and will place the data on the class of devices or tier that is most appropriate for the block of data.
Storage pools allocate and store data in 1 GB slices, these slices can be migrated or relocated allowing FAST to reorganize LUNs onto different tiers of the pool seamlessly to the hosts accessing the LUNs.