text: (cid:2) Volumes can be compressed. 
  
  (cid:2) Volumes can be configured as VMware vSphere Virtual Volumes, sometimes referred to 
  as*VVols*, which allows VMware vCenter to manage storage objects. The storage system 
  administrator can create these objects and assign ownership to VMware administrators to 
  allow them to manage these objects. 
  
  Volumes have two major modes: Managed mode and image mode. For managed mode 
  volumes, the sequential policy and the striped policy define how the extents of the volume 
  are allocated from the storage pool. 
  
  (cid:2) Volumes can be replicated synchronously or asynchronously. An IBM Spectrum Virtualize 
  system can maintain active volume mirrors with a maximum of three other IBM Spectrum 
  Virtualize systems, but not from the same source volume. 
  
  These volume characteristics are described next. 
  
  **7.1.3 I/O operations data flow**
  
  Volumes can have one or two copies. Although a mirrored volume looks to its users the same 
  as a volume with a single copy, some differences exist in how I/O operations are performed 
  internally for volumes with single or two copies. 
  
  When host requests an I/O operation to any IBM Spectrum Virtualize volume type, the 
  multipath driver on the host identifies the preferred node for the volume and by default uses 
  only paths to this node to communicate I/O requests. 