Patent ID: 7080221

Claim:
A method for performing a data migration in a clustered computer system including at least two hosts and at least one storage system that stores data shared by the hosts, the at least one storage system providing a plurality of storage volumes to the hosts to store data shared by the at least two hosts, the plurality of storage volumes including at least one first storage volume and at least one second storage volume, the method comprising acts of: (A) migrating data from the at least one first storage volume to the at least one second storage volume under the control of a transfer utility that is external to the at least one storage system, the at least one first storage volume being allocated to at least one application program installed on each of the at least two hosts in the clustered computer system to store data written by the at least one application program wherein the transfer utility reads the data from the at least one storage system that provides the first storage volume to at least one intermediate component and writes the data from the at least one intermediate component to the at least one storage system that provides the second storage volume; and (B) maintaining the at least one first storage volume available to the at least one application program so that write operations from the at least one application program can be performed to the at least one first storage volume during the act of migrating.