Described is a distributed copying technique that may be used in migrating
large amounts of data from one or more source devices to one or more
destination devices. The data source is divided into partitions. As Fibre
Channel adapters (FAs) become available, each of the FAs may copy a
partition of the data. A copy indicator value indicates the last
partition delegated to an FA for copying. The last FA to complete copying
is responsible for ensuring completed copying of any other data
partitions delegated to an FA which has died during migration of the
other data partitions. In the event that the last FA dies prior to
completing its processing, additional steps are performed by other
remaining FAs to copy all data partitions not known to be successfully
migrated.