You can take a snapshot of a boot environment, for backup or tracking purposes, at any stage during modifications by using the beadm create command.
# beadm create BeName@snapshotNamedescription
where BeName is the name of an existing boot environment that you want to make a snapshot from. Type a custom snapshotdescription to identify the date or purpose of the snapshot.
Although a snapshot is not bootable, you can create a boot environment based on that snapshot by using the -e option in the beadm create command. Then you can use the beadm activate command to specify that this boot environment becomes the default boot environment on the next reboot.
You can use the beadm list -s command to view the available snapshots for a boot environment.