Boot Environments

Boot Environments are bootable clones of snapshots of the working system. Boot Environments allow you to create a safe fallback Boot Environment before upgrading or making major changes to the system.

Other applications may create Boot Environments automatically before performing critical operations such as major operating system upgrades.

Warning

Boot Environments by default do not cover all locations, such as /home where your personal data is usually stored.

The Boot Environments preferences application lets you view, create, remove, mount, and boot into Boot Environments.

Note

Boot Environments functionality cannot be used when the system is running from Live media. It can only be used when the system has been installed to a disk.

Viewing Boot Environments

Open the Boot Environments preferences application. If you have a user password set, you will be asked to enter your credentials. Only users in the administrative group (wheel) can use the Boot Environments application by default.

You will see the available Boot Environments.

Creating Boot Environments

To create a new Boot Environment, click New… and enter a name for the new Boot Environment.

Removing Boot Environments

Select a Boot Environment by clicking on it, and then press Remove. Note that you cannot remove the currently active Boot Environment.

Mounting Boot Environments

You can make available, or “mount”, existing Boot Environments, e.g., in order to inspect them or to copy files from there.

To do this, select a Boot Environment by clicking on it, and then press Mount. Note that you cannot mount the currently active Boot Environment since it is already mounted at /.

The selected Boot Environment will be mounted, and a Filer window will be opened at the mountpoint of the Boot Environment.

Booting into a Boot Environment

Activate a Boot Environment by checking its checkbox, and then press Restart…. The computer will restart into the selected Boot Environment.

You can also select which Boot Environment to start into from the bootloader. Starting with helloSystem 0.8.1, press the press the Backsapce key on your keyboard as soon as the screen becomes grey. Then use the FreeBSD bootloader menu to choose a Boot Environment and to start the system. Note that choosing a Boot Environment this way does not change the default Boot Environment, and will affect the current boot only.

More Information

Advanced users can use the bectl command on the command line, which the Boot Environments preferences application is using under the hood.

For more information regarding Boot Environments, please refer to the ZFS Boot Environments presentation by Sławomir Wojciech Wojtczak.