Is the application in a VMware environment? If so, you can use storage vMotion for the migration.
What is the application that you are trying to migrate?
Your best bet in this situation is to utilize host-based utilities:
1. VMware - storage vmotion as Avi points out
2. UNIX - Native LVM usage for migrations
3. Windows - Open Migrator (EMC Tool) or native Windows mirroring/robocopy.