text: **11.6.16 Thin-provisioned background copy**
  
  MM/GM relationships preserve the space-efficiency of the master. Conceptually, the 
  background copy process detects a deallocated region of the master and sends a special 
  *zero buffer*to the auxiliary. 
  
  If the auxiliary volume is thin-provisioned and the region is deallocated, the special buffer 
  prevents a write and, therefore, an allocation. If the auxiliary volume is not thin-provisioned or 
  the region in question is an allocated region of a thin-provisioned volume, a buffer of “real” 
  zeros is synthesized on the auxiliary and written as normal. 
  
  **11.6.17 Methods of synchronization**
  
  This section describes two methods that can be used to establish a synchronized 
  relationship. 
  
  **Full synchronization after creation**
  The full synchronization after creation method is the default method. It is the simplest method 
  in that it requires no administrative activity apart from issuing the necessary commands. 
  However, in certain environments, the available bandwidth can make this method unsuitable. 
  
  Use the following command sequence for a single relationship: 
  
  (cid:2) Run**mkrcrelationship**without specifying the**-sync**option. 
  (cid:2) Run**startrcrelationship**without specifying the**-clean**option. 