HAMMER snapshot and mirror vs ZFS snapshot and clone

[Predrag Punosevac]

Could a kind soul point me to the additional documentation besides 
man hammer(5) and man hammer(8) which will help me further understand
the difference in use/purpose of HAMMER snapshot and
mirror-copy/mirror-stream on the production file server? I am also
interested to hear from gurus what is the main difference of HAMMER
snapshot vs ZFS snapshot and also how does mirror-copy/mirror-stream
compares to ZFS clone. 

My confusion in part comes from the fact that HAMMER has build in
history which is non-existing on ZFS so it seems that snapshots are kind
semi-redundant if the history is enabled. Of course history might be
very expensive in terms of disk space as I learned hard way about half a
year ago so turning off history and taking HAMMER snapshots instead
might be desirable in some situations. 

Could anybody point me to any examples of mirror-stream via ssh to a
remote machine. Is there a way to encrypt mirror-stream on the fly when
doing it to a remote location? 

Most Kind Regards,
Predrag

P.S. I read serveral times over HAMMER crash course posted on BSD now.