text: **Managed disk group (storage pool)**
  See “Storage pool (managed disk group)” on page 786. 
  
  **Managed mode**
  An access mode that enables virtualization functions to be performed. See also “Image 
  mode” on page 778 and “Unmanaged mode” on page 787. 
  
  **Maximum replication delay**
  Maximum replication delay is the number of seconds that Metro Mirror or Global Mirror 
  replication can delay a write operation to a volume. 
  
  **Master volume**
  In most cases, the volume that contains a production copy of the data and that an application 
  accesses. See also “Auxiliary volume” on page 770, and “Relationship” on page 784. 
  
  **Metro Global Mirror**
  Metro Mirror Global is a cascaded solution where Metro Mirror synchronously copies data to 
  the target site. This Metro Mirror target is the source volume for Global Mirror that 
  asynchronously copies data to a third site. This solution has the potential to provide disaster 
  recovery with no data loss at Global Mirror distances when the intermediate site does not 
  participate in the disaster that occurs at the production site. 
  
  **Metro Mirror**
  Metro Mirror (MM) is a method of synchronous replication that maintains data consistency 
  across multiple volumes within the system. Metro Mirror is generally used when the write 
  latency that is caused by the distance between the source site and target site is acceptable to 
  application performance. 