Incremental forever on ZFS

general discussion
1

If the incremental forever method is used on ZFS for image and file:

  1. Does urbackup only write the changed blocks of the image into the volume after snapshotting it? I.e. even without ZFS deduplicatin only the space of changed blocks is consumed?

  2. If urbackup backs up a changed file (z.b. a large VMWARE vmdk-Image from a client), does it only write the changed blocks of the file? I.e. even without ZFS deduplication only space of changed portions woult be consumed?