zrep simplifies ZFS replication for the use-case we’re demonstrating. However, we’ll also discuss many concepts and aspects of ZFS that are not specific to zrep. zrep itself is not available from ports, but it only consists of a single shell script. The stable version of zrep needs ksh as its operating shell, though the newer version from GitHub can also use bash. The script needs to be installed in a directory that is included in $PATH on both systems. On FreeBSD, you may want to change the first line to point to the correct location of ksh or bash in /usr/local/bin.

Initially, it may also be useful to setup keys to allow password-less ssh logins for root between the two systems. This was covered in the article Introduction to ZFS Replication. You may later prefer an alternative to ssh and perhaps to use zfs allow to avoid using root but a familiar tool like ssh is convenient.