ZFS Boot Environments Are Helping To Improve The Resilience Of FreeBSD Upgrades

Besides the ZFS file-system just being a heck of a lot better all-around than FreeBSD's traditional UFS, tooling around ZFS paired with its native snapshot capabilities is allowing for more resilient installations and upgrades of FreeBSD.

FreeBSD developer Allan Jude talked at last weekend's FOSDEM conference about "magic upgrades" in making FreeBSD system upgrades atomic, safe, and fast by leveraging ZFS Boot Environments.

This is basically about allowing the root file-system with just the OS installation (and not the user data or configuration files) to be snapshot each time around an OS upgrade. This allows for easily rolling back in case of failures. Tooled down to the boot-loader, it can also be easily switched to a different state of the OS there so the system is a lot more forgiving in case of any problems.

The concept is akin to SUSE/openSUSE zypper integration around Btrfs for snapshots and allowing easy roll-backs and transactional upgrades. Years ago when Fedora was pursuing Btrfs, they also had system snapshots around upgrades with Btrfs and tied into the Yum package manager.

The ZFS Boot Environments with FreeBSD is similar to those other efforts, though seems to allow for more advanced system configurations and setups. Should you be interested in learning more about these FreeBSD "magic" updates with ZFS, see these detailed slides by Allan Jude from FOSDEM 2019.