overwriteMode

Specifies whether DataSync should modify or preserve data at the destination location.

• ALWAYS (default) - DataSync modifies data in the destination location when source data (including metadata) has changed.If DataSync overwrites objects, you might incur additional charges for certain Amazon S3 storage classes (for example, for retrieval or early deletion). For more information, see Storage class considerations with Amazon S3 transfers.

• NEVER - DataSync doesn't overwrite data in the destination location even if the source data has changed. You can use this option to protect against overwriting changes made to files or objects in the destination.