The non-disruptive data migration feature can be provided by a storage array or by a storage virtualization technology. It allows data to be copied to a new physical location while the host continues to provide input/output access to the existing mapped LUN. Once the data is copied to the new location, it can then be re-mapped and it will free space on the storage it was moved from.
This is beneficial because downtime in an environment often requires planning, and many businesses can't afford to have long periods of downtime. That means disruptive migrations must be performed quickly. Migration projects are common for tasks such as implementing a new storage system, freeing up capacity on an existing device or moving data as part of an information lifecycle plan.