Patent ID: 7917713

Claim:
A method of migrating data from a source device to a target device in a storage system, comprising: dividing a capacity of the source device into a plurality of sub-regions by a controller; locking the sub-regions from storage activity by the controller; establishing a mirroring relationship for write data updates between the source device and the target device by the controller; writing second data to the plurality of sub-regions in the source device by the controller; writing a first portion of the second data to first corresponding sub-regions in the target device if the first corresponding sub-regions have previously had first data copied from the plurality of sub-regions; assigning a local processor to copy a second portion of the second data from the source device to second corresponding sub-regions in the target device by the controller if the second corresponding sub-regions have not previously had first data copied from the plurality of sub-regions; and copying the second portion of the second data from the source device to second corresponding sub-regions in the target device, wherein copying comprises: reading data from one of the plurality of sub-regions by the local processor; and writing data to an identical location on the target device by the local processor, wherein the steps of establishing the mirroring relationship for write data updates between the source device and the target device and locking the sub-regions from storage activity are performed in parallel.