There is disclosed a data synchronization apparatus for maintaining synchronization between a source data file and a copy data file. The data synchronization apparatus comprises: 1) a bulk copy controller for copying a plurality of data records from the source data file to the copy data file; and 2) an update controller for detecting a change in a data record previously copied by the bulk copy controller from the source data file to the copy data file and copying the changed data record from the source data file to the copy data file.