The repository is updated periodically using scheduled resynchronizations. This method involves a scan of the source machine’s file system. With batch resynchronization, the changed blocks are transferred. By default, the block size that is transferred is 2 MB; it is 16 KB if fine change detection is configured in the store template for Gen 1 repositories or in the Policy definition for Gen 2 repositories. An entire file is transferred if it is less than one block. Batch backup is useful for data that does not change often, such as data contained on the operating system disk.
Fine change detection should be used with the batch mover if there are frequent, widely distributed changes to files. Typically however, content on file servers does not benefit from fine change detection, because Microsoft Office documents are automatically compressed by the applications. This means that the smallest of modification causes a completely different file to be created, negating any benefit from detecting changed blocks.