text: Cold demote occurs between tiers 2 and 3 only. 
  
  (cid:2) Expanded cold demote 
  
  Demotes appropriate sequential workloads to the lowest tier to better use nearline tier 
  bandwidth. 
  
  (cid:2) Swap 
  
  A swap moves a “hot” extent from a lower performance disk tier to a higher disk tier while 
  simultaneously moving a “cold” extent from the higher disk tier to a lower performance disk 
  tier. 
  
  Extent migration occurs at a maximum rate of 12 GB every 5 minutes for the entire system. It 
  prioritizes the following actions: 
  
  (cid:2) Promote and rebalance get equal priority 
  (cid:2) Demote is guaranteed 1 GB every 5 minutes, and then gets whatever is left 
  
  **Note:**Extent promotion or demotion only occurs between adjacent tiers. In a three-tier 
  storage pool, Easy Tier does not move extents from a flash tier directly to nearline tier or 
  vice versa without moving to the enterprise tier first. 
  
  The Easy Tier overload protection is designed to avoid overloading any type of MDisk with too 
  much work. To achieve this, Easy Tier needs to have an indication of the maximum capability 
  of a managed disk. 
  
  For an array made of locally attached drives, the system can calculate the performance of the 
  MDisk because it is pre-programmed with performance characteristics for different drives. For 
  a SAN-attached managed disk, the system cannot calculate the performance capabilities, so 
  the system has a number of predefined levels that can be configured manually for each 
  MDisk. This is called the Easy Tier load parameter (low, medium, high, very_high). 