Method and apparatus for data migration are described herein. In one
embodiment, in response to data received from an application to be
written to a first storage volume, the data is written to the first
storage volume and a second storage volume substantially concurrently.
When the first and second storage volumes are synchronized, a switchover
is performed from the first storage volume to the second storage volume,
such that subsequent data received from the application is written to the
second storage volume, where writing the data to the first and second
storage volumes and the switchover are performed without knowledge of the
application. Other methods and apparatuses are also described.