Chapter 6. Storage pools 231
Modify site
This action is available only for systems that use HyperSwap. Select Modify Site to change 
the site with which the external controller is associated, as shown in Figure 6-51.
Figure 6-51   Modifying the site of an external controller
To change controller site assignment with CLI, use chcontroller. Example 6-24 shows 
controller0 renamed and reassigned to a different site.
Example 6-24   Changing controller’s name and site 
IBM_Storwize:ITSOV7K:superuser>chcontroller -name site3_controller -site site3 controller0
IBM_Storwize:ITSOV7K:superuser>
6.3.3  Working with external MDisks
After an external back-end system is configured, attached to IBM Storwize V7000, and 
detected as a controller, you can work with LUs that are provisioned from it.
External LUs can have one of the following modes on Storwize V7000:
/SM590000Unmanaged
External MDisks are discovered by the system as unmanaged MDisks. An unmanaged 
MDisk is not a member of any storage pool. It is not associated with any volumes, and has 
no metadata stored on it. The system does not write to an MDisk that is in unmanaged 
mode, except when it attempts to change the mode of the MDisk to one of the other 
modes.
/SM590000Managed
When unmanaged MDisks are added to storage pools, they become managed. Managed 
mode MDisks are always members of a storage pool, and their extents contribute to the 
storage pool. This mode is the most common and normal mode for an MDisk.
/SM590000Image
Image mode provides a direct block-for-block translation from the MDisk to a volume. This 
mode is provided to satisfy the following major usage scenarios:
– Virtualization of external LUs that contain data that was not written through the 
Storwize V7000.
– Exporting MDisks from the Storwize V7000 after migration of volumes to image mode 
MDisks.