text: Depending on the size, age, and technology level of the disk storage system, the total 
  available cache in the system can be larger, smaller, or about the same as the cache that is 
  associated with the disk storage. Because hits to the cache can occur in either the IBM 
  Storwize V7000 or at the disk controller level of the overall system, the system as a whole can 
  take advantage of the larger amount of cache wherever the cache is located. Therefore, if the 
  storage controller level of the cache has the greater capacity, expect hits to this cache to 
  occur, in addition to hits in the IBM Storwize V7000 cache. 
  
  Also, regardless of their relative capacities, both levels of cache tend to play an important role 
  in enabling sequentially organized data to flow smoothly through the system. The IBM 
  Storwize V7000 cannot increase the throughput of the underlying disks in all cases because 
  this increase depends on both the underlying storage technology and the degree to which the 
  workload exhibits*hotspots*or sensitivity to cache size or cache algorithms. 
  
  IBM Spectrum Virtualize V7.3 introduced a major upgrade to the cache code. In association 
  with IBM Storwize V7000 Gen2 hardware, it provided another cache capacity upgrade. 