text: **11.6 Remote Copy services**
  
  This section describes the Remote Copy services, which are a synchronous remote copy 
  called Metro Mirror (MM), asynchronous remote copy called Global Mirror (GM), and Global 
  Mirror with Change Volumes. Remote Copy in an IBM Spectrum Virtualize system is similar to 
  Remote Copy in the IBM System Storage DS8000 family at a functional level, but the 
  implementation differs. 
  
  IBM Spectrum Virtualize provides a single point of control when remote copy is enabled in 
  your network (regardless of the disk subsystems that are used) if those disk subsystems are 
  supported by the system. 
  
  The general application of remote copy services is to maintain two real-time synchronized 
  copies of a volume. Often, the two copies are geographically dispersed between two IBM 
  Spectrum Virtualize systems. However, it is possible to use MM or GM within a single system 
  (within an I/O Group). If the master copy fails, you can enable an auxiliary copy for I/O 
  operations. 
  
  **Tips:**Intracluster MM/GM uses more resources within the system when compared to an 
  intercluster MM/GM relationship, where resource allocation is shared between the 
  systems. Use intercluster MM/GM when possible. For mirroring Volumes in the same 
  system, it is better to use Volume Mirroring or the FlashCopy feature. 