A method and apparatus for managing a migration of a data set from at
least one first storage location to at least one second storage location,
wherein read requests to the data set from at least one application
program executing on a computer system initially are serviced from the at
least one first storage location. The data set is copied from the at
least one first storage location to the at least one second storage
location, and then at least one aspect of the computer system is modified
so that read requests to the data set are serviced from the at least one
second storage location to achieve the migration. In one embodiment, the
migration is subsequently undone by modifying the at least one aspect of
the computer system so that read requests to the data set are again
serviced from the at least one first storage location. In another
embodiment, after the migration is performed, a determination is made as
to whether to finalize the migration.