text: **10.3 Unmap**
  
  Spectrum Virtualize systems running V8.1.0 and later support the SCSI Unmap command. 
  This enables hosts to notify the storage controller of capacity that is no longer required, which 
  can improve capacity savings. 
  
  **10.3.1 SCSI unmap command**
  
  Unmap is a set of SCSI primitives that allow hosts to indicate to a SCSI target that space 
  allocated to a range of blocks on a target storage volume is no longer required. This 
  command allows the storage controller to take measures and optimize the system so that the 
  space can be reused for other purposes. 
  
  The most common use case, for example, is a host application, such as VMware freeing 
  storage within a file system. The storage controller can then optimize the space, such as 
  reorganizing the data on the volume so that space is better used. 