IBM V7000 Introduction And Implementation Manual page 367

Any imported MDisk that has not been migrated into a pool yet is listed under Pools 
System Migration (Figure 8-41).
Figure 8-41 Imported MDisk in the System Migration window
This feature is normally used as a method to migrate data from existing external LUNs into
storage pools, either located internally or externally, on IBM Flex System V7000 Storage
long-term solution
Node. You should not use image mode volumes as a for reasons of
performance and reliability.
To migrate an image mode volume into a regular storage pool, select the volume to be
migrated and click Actions  Start Migration.
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Chapter 8. Storage pools