text: (cid:2) Number of paths per host multipath device 
  
  The maximum supported number of paths per multipath device that is visible on the host is 
  eight. Although the IBM Subsystem Device Driver Path Control Module (SDDPCM), 
  related products, and most vendor multipathing software can support more paths, the 
  Storwize V7000 expects a maximum of eight paths. In general, you see only an effect on 
  performance from more paths than eight. Although the IBM Spectrum Virtualize can work 
  with more than eight paths, this design is technically unsupported. 
  
  (cid:2) Do not intermix dissimilar array types or sizes 
  
  Although the IBM Spectrum Virtualize supports an intermix of differing storage within 
  storage pools, it is best to always use the same array model, Redundant Array of 
  Independent Disks (RAID) mode. RAID size (RAID 5 6+P+S does not mix well with RAID 6 
  14+2), and drive speeds. 
  
  Rules and guidelines are no substitution for monitoring performance. Monitoring performance 
  can provide a validation that design expectations are met, and identify opportunities for 
  improvement. 
  
  **IBM Spectrum Virtualize performance perspectives**
  
  IBM Spectrum Virtualize software was developed by the IBM Research Group. It is designed 
  to run on commodity hardware (mass-produced Intel-based processors [CPUs] with 
  mass-produced expansion cards) and to provide distributed cache and a scalable cluster 
  architecture. One of the main goals of this design was to use refreshes in hardware. Currently, 
  the Storwize V7000 cluster is scalable up to eight nodes (four control enclosures). 