I have a similar question on my list. If I keep my work on a local drive and then copy the directory to the ZFS server each day, I want to avoid sending the entire thing all over again (or reading the old over the network to determine it is the same). So I want something that cooperates with the server to determine what needs to be sent.
I thought I noticed rsync mentioned in the manual. Is that indeed running on FreeNAS and useful for sync'ing a Windows machine using NTFS?
I use Unison for my web server. It's a pain because the versions must match exactly and that's difficult across platforms. But, is Unison running on FreeNAS, available as a module, or what?