Take a look at zrepl https://zrepl.github.io/
It can leverage things like zfs bookmarks and resumable send.  I am currently using it to backup my main illumos box to a secondary box at home as well as an offsite box.
There’s also a basic example setup on the omnios website https://omnios.org/info/zrepl 

On Aug 9, 2024, at 10:36 AM, Gabriele Bulfon via illumos-developer <developer@lists.illumos.org> wrote:

Hi,
 
I have some production systems doing a daily sync replica on a dedicated storage backup system.
They're all organized into datasets of the main backup pool.
Sync is via ssh using "zfs send -R -i ... | ssh host " zfs receive -Fduv ...".
The destination machine is always aligned to the same snaps existing at the source, removing old ones when no more at the source.
Is there a way to change this behaviour and let the destsination sync to new snaps but keep older ones?
The aim is to have another process on the backup machine to do its own send to another backup machine, with its own timings, and this second process will take care of removing old snaps when they're no more needed.
Znapzend is not an option, because it's not a real replica tool for zone datasets as it is not replicating all properties.
 
Thanks,
G