text: **9.1 Storage migration overview**
  
  To migrate data from a storage system to the Storwize V7000, it is necessary to use the 
  built-in external virtualization capability. This capability places external connected Logical 
  Units (LUs) under the control of the Storwize V7000. After volumes are virtualized, hosts 
  continue to access them, but do so through the Storwize V7000, which acts as a proxy. 
  
  **Attention:**The system does not require a license for its own control and expansion 
  enclosures. However, a license is required for each enclosure of any external systems that 
  are being virtualized. Data can be migrated from storage systems to your system by using 
  the external virtualization function within 45 days of purchase of the system without 
  purchase of a license. After 45 days, any ongoing use of the external virtualization function 
  requires a license for each enclosure in each external system. 
  
  Set the license temporarily during the migration process to prevent messages that indicate 
  that you are in violation of the license agreement from being sent. When the migration is 
  complete, or after 45 days, reset the license to its original limit or purchase a new license. 