A customer has no available floor space for expansion and room for only one disk enclosure pair in their DS8700. Four disk enclosure pairs are required to meet the current I/O needs of a data warehousing application. They are only utilizing 10% of their total capacity. Another application workload needs to be added to the system but requires two disk enclosure pairs. The customer is considering SSD and Easy Tier. 
Which of the following is the primary function of Easy Tier（）