So you add a large amount of data, you snapshot, you delete that data and at that point you send the snapshot but don&#x27;t want to send the deleted data? Why not just re-snapshot and send the new snapshot instead of the old one?<p>&gt; And I&#x27;m also unsure whether it&#x27;s even possible interrupt a transfer and resume it later, if the underlying data has changed<p>There is no &quot;underlying data has changed&quot; in a snapshot, it&#x27;s a revision of the filesystem. As for interrupting and resuming later, Delphix apparently has contributed a resumable zfs send&#x2F;receive to OpenZFS, though I don&#x27;t know if it&#x27;s available in yours or rsync.net&#x27;s distribution: <a href="http:&#x2F;&#x2F;blog.delphix.com&#x2F;matt&#x2F;2015&#x2F;03&#x2F;25&#x2F;resumable-zfs-sendreceive&#x2F;" rel="nofollow">http:&#x2F;&#x2F;blog.delphix.com&#x2F;matt&#x2F;2015&#x2F;03&#x2F;25&#x2F;resumable-zfs-sendre...</a><p>As for the concerns of sending small files first, I don&#x27;t think ZFS could even use that: I don&#x27;t believe it&#x27;s content-addressed, so if you send a set of blocks from snapshot 1, interrupt and send snapshot 2 instead the blocks common to both will still be re-sent, ZFS only knows the block commonality from snapshots and since snapshot 1 hasn&#x27;t been pushed its contents can&#x27;t be used for snapshot 2. Unless the resumable replication support uses content addressing  but that doesn&#x27;t seem to be the case.