User oshogbo shows us how to bring zpool checkpoints to the FreeBSD operating system bootloader. What that means is, when you start up your FreeBSD system, you will see a checkpoint of your ZFS pool, before your operating system even loads. Check out the link below for the full set of instructions.

Bringing zpool checkpoints to a FreeBSD bootloader: https://oshogbo.vexillium.org/blog/79/