Rsynced iSCSI share

[libmax]

I have no idea if this is possible and I'm hoping someone can shed some light on this for me.
We have two freenas boxes both set up the same way. So 8 disks in a zfs2 configuration. Box1 pushes via rsync all of it's data to Box2.
Part of the data on Box1 is an iSCSI share (file extent running off of a zvol). Is there a way for me to set up an iSCSI share on Box2 that will allow me to view the data that is being sent to it from Box1?
I tried setting up an on Box2 extent that used the extent from Box1 but it just overwrote the original and created a new one with the same name and thusly no data.

Any thoughts on this would be greatly appreciated. (And let me know what other information you may need please).
System Specs:
Build FreeNAS-9.10.2-U3 (e1497f269)
Platform Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz
Memory 65395MB
Thanks!

 

[mav@]

Instead of rsync it is better to use ZFS replication between FreeNAS boxes, since it can properly replicate ZVOL changes. After replication complete first time, you should be able to create read-only iSCSI extent on the Box2 to see the data.

 

[libmax]

@mav@ That was our original plan but if we do snapshots we're effectively (if I'm understanding this right) halving our storage capacity aren't we? Because the snapshots on box1 will take up as much space as the data that's already on there. Unless it's possible to only store snapshots on box2?
Thanks for your help.

 

[mav@]

Snapshots take absolutely no space until new data is written to the same blocks. So there indeed can be some additional pool space usage if there are many writes within snapshot life time, but using ZFS without using snapshots is a dropping most of its Copy-on-Write benefits. I'd recommend you to use snapshots at least for safety purposes against unwanted data deletions or modifications.