describes using ZFS to create bootable backups of your operating system's kernel and userland. With Boot Environments, you can make the riskiest sysadmin tasks boring, allowing you to easily revert changes after an upgrade or major configuration change.

Track evicted cache headers to fine-tune the balance between MRU and MFU automatically. Kernel Optimization in FreeBSD

Encryption is defined at dataset creation time. The encryption wrapping key can be managed via a raw file, a passphrase, or a key management system:

is a treasure trove of practical guides, including splitting mirrored pools, deleting multiple neighboring snapshots, recovering destroyed pools, and using the ZFS debugger ( zdb ) to examine your datasets in detail.