text: The**Detect MDisk**commands must be run following the creation or modification (addition 
  of or removal of MDisk) of storage pools for paths to be redistributed. 
  
  If your back-end storage system does not support the Storwize V7000 round-robin algorithm, 
  ensure that the number of MDisks per storage pool is a multiple of the number of storage 
  ports that are available. This approach ensures sufficient bandwidth for the storage controller, 
  and an even balance across storage controller ports. 
  
  In general, configure disk subsystems as though Storwize V7000 was not used. However, 
  there might be specific requirements or limitations as to the features usable in the specific 
  back-end storage system when it is attached to Storwize V7000. Review the appropriate 
  section of documentation to verify that your back-end storage is supported and to check for 
  any special requirements at this website. 
  
  Observe the following general rules: 
  
  (cid:2) Disk drives 
  
  Exercise caution with the use of large hard disk drives so that you do not have too few 
  spindles to handle the load. 
  
  (cid:2) Array sizes: 
  
  – Storwize V7000 does not queue more than 60 I/O operations per MDisk. Therefore, 
  
  make sure that the MDisks presented to Storwize V7000 can handle about this many 
  requests, which corresponds to about 8 HDDs. If your array can handle higher load, 
  split it in several LUNs of equal size to better match back-end storage capabilities with 
  the load that Storwize V7000 can generate. 
  
  For more information about back-end storage LUN presentation to Storwize V7000, 
  see IBM System Storage SAN Volume Controller and Storwize V7000 Best Practices 
  and Performance Guidelines, SG24-7521. 
  
  – Since version 7.3, the system uses autobalancing to restripe volume extents evenly 
  across all MDisks in the storage pools. 