IBM DS8000 Easy Tier® is an optional, no-charge feature of the IBM® System Storage® DS8700, DS8800, and DS8870.
Easy Tier can move logical volume extents between disk ranks within an extent pool to provide automated hot spot management. Extents of a logical volume that are considered “hot” can be promoted to a higher tier of disk. Extents that are considered “cold” and that have no or little I/O activity can be demoted to a lower tier of disk. On which disk tier, such as Solid-State Drive (SSD), Enterprise, or Nearline, a volume currently has extents might be of interest for various reasons, including possible chargeback or cost recovery for high performance disk tier use.
This IBM Redpaper™ publication contains a sample script that provides an example of the coding technique for those individuals interested in implementing a chargeback capability.