A system migrates data between a source device and a target device in a storage system. A processor is operational within a local domain of the storage system. A redundant array of independent disks (RAID) controller electrically connected to the processor. The RAID controller divides a capacity of the source device into a plurality of sub-regions, locks the sub-regions from storage activity, establishes a mirroring relationship for write data updates between the source device and target device, and assigns the processor to copy data from the source device to the target device. A method of migrating data includes dividing a capacity of a source device into a plurality of sub-regions, locking the sub-regions from storage activity, establishing a mirroring relationship for write data updates between the source device and a target device, and assigning a local processor to copy data from the source device to the target device.