LU on ZFS use snapshots for create new BE, so You can use snapshots for store current state but ....
Snapshots is not backup, becouse not covered all cases.
Some examples when snapshots not help:
- ZFS pool is courrupted. ( Or you lost 2 or more disks on Your raid 5).
- You upgrade zpool after patching. Old kernel can not use new version of pool.
So You should have backup on other media in any case.
In case You will try use snapshot:
- Check free spaces on zpool.
For retrun to initial state you can use:
- rollback FS to snapshot ( not recommend, becouse You lost patched state)
- create clone FS from snapshot.
After this you should substitue mount point for new cloned FS.
May be need change configuration of zones ( I do not know how /var mounted at zone)
need change properties of rpool (specify bootfs )