This tutorial by user shows us how to set up ZFS snapshots on your FreeBSD system. The guide is in two parts and starts with setting up the zpool for snapshots then incremental snapshots. You may view the full set of instructions at the links below.

A very nice way to do a live backup of your server/work station is with ZFS snapshots, of course, if you use ZFS.
You can send a snapshot to: a file, the local system, via ssh, via netcat and who know what else.
I’m going to cover how to do incremental snapshots to your local system using a USB drive.
To do zfs snapshot, zfs send & zfs receive  you are going to need elevated permissions. Always be extremely careful with ZFS operations because you can easily destroy all of your data! The following commands worked for me but might not work for you, alway be sure before you execute a command, do NOT copy&paste them from here.

  • Connect the drive, look what’s coming up in /var/log/messages. Let’ say is da0
  • Check the disk and create a new zpool

Full Tutorial:

ZFS snapshot on FreeBSD
ZFS snapshot on FreeBSD – Part 2