Note the "Should sync?" parameter "nosync" means that the two mirrors are
already in sync which will be the case on a clean shutdown of Windows. If the
mirrors are not clean, you can specify the "sync" option instead of "nosync"
-and the Device-Mapper driver will then copy the entirey of the "Source Device"
+and the Device-Mapper driver will then copy the entirety of the "Source Device"
to the "Target Device" or if you specified multipled target devices to all of
them.