text: Before enabling SCSI unmap, see this IBM Support web page. 
  
  Analyze your storage stack to optimally balance advantages and costs of data reclamation. 
  
  **7.1.12 Virtual volumes**
  
  IBM Spectrum Virtualize V7.6 introduced support for*virtual volumes*. These volumes enable 
  support for VMware vSphere Virtual Volumes (VVols), which allow VMware vCenter to 
  manage system objects, such as volumes and pools. The IBM Spectrum Virtualize system 
  administrators can create volume objects of this class, and assign ownership to VMware 
  administrators to simplify management. 
  
  For more information about configuring VVol with IBM Spectrum Virtualize, see Configuring 
  VMware Virtual Volumes for Systems Powered by IBM Spectrum Virtualize, SG24-8328. 
  
  **7.1.13 Volumes in multi-site topologies**
  
  IBM Spectrum Virtualize system can be set up in a multi-site configuration, which makes the 
  system aware of which system components (I/O groups, nodes, and back-end storage) are at 
  which site. For the purpose of defining the storage topology, a site is defined as an 
  independent failure domain, which means that if one site fails, the other site can continue to 
  operate without disruption. 
  
  The sites can be in the same data center room or across rooms in the data center, in buildings 
  on the same campus, or buildings in different cities, depending on the type and scale of a 
  failure the solution must survive. 