Although large volume sizes may be one of the important criteria in determining the time that is taken for Automatic Synchronization to complete, in many cases only about 50 percent of the volumes are used.

This results in the synchronization process sending unused blocks to the Secondary, therefore taking a longer time to complete and causing an overhead on the network bandwidth.

The SwiftSync feature enables Volume Replicator to perform intelligent synchronization by replicating only those blocks that the application uses. In some cases these blocks may just have the file system on them. Because only the used blocks are transferred, the synchronization is much faster and allows for more efficient usage of the available network bandwidth.

By default, Volume Replicator performs intelligent synchronization for volumes with NTFS or ReFS file systems, however if required you can choose to disable this feature.