Trying Out Ubuntu 20.04 With ZFS + Zsys Automated APT Snapshots
It was with Ubuntu 19.10 that Canonical added a ZFS root file-system install option to their Ubiquity desktop installer. That easy install option is there with Ubuntu 20.04's desktop installer but is now tucked away within an "advanced features" windows.
From Ubiquity's "advanced features" area is the ability to install to a ZFS root file-system. The option is still considered experimental while EXT4 remains their default file-system. Opting for the ZFS On Linux option will also install their Zsys daemon by default.
After going ahead with the Ubuntu 20.04 daily ISO with ZFS and rebooting the system, when carrying out any APT transactions there is the new "saving system state" message. Running APT will trigger Zsys to take a ZFS snapshot should any package upgrade/install/removal go awry.
Via the GRUB boot-loader is a "history" menu.
From that history menu, one can select an earlier snapshot for booting to.
The behavior and GRUB handling of the snapshots is just like the Fedora Btrfs system rollback option from a decade ago and also what's been offered on SUSE/openSUSE. So far it seems to be working out fine and a nice addition for those running with Ubuntu 20.04's experimental ZFS support.