Boot Screen
4 minute read.
Last Modified 2021-03-31 15:09 EDTTrueNAS supports a ZFS feature known as boot environments. These are snapshot clones that TrueNAS can boot into. Only one boot environment can be used for booting.
Go to System > Boot to see a boot environment list.
To view the list of boot environments on the system, go to System > Boot. Each boot environment entry contains this information:
- Name: the name of the boot entry as it appears in the boot menu.
- Active: indicates which entry boots by default if a boot environment is not active.
- Created: indicates the boot environment creation date and time.
- Space: shows boot environment size.
- Keep: indicates whether or not TrueNAS deletes this boot environment when a system update does not have enough space to proceed.
To access more options for a boot environment, click :
-
), underscores (_
), and periods (.
) are allowed.-
), underscores (_
), and periods (.
) are allowed.Click ACTIONS to:
Make a new boot environment from the active environment:
Only alphanumeric characters, dashes (-
), and underscores (_
) are allowed in the Name.
Name the new boot environment and click SUBMIT.
Sometimes, rolling back to an older boot environment can be useful. For example, if an update process doesn’t go as planned, it is easy to roll back to a previous boot environment. TrueNAS automatically creates a boot environment when the system updates.
There are two different methods for changing the active boot environment: using the web interface and through a Command Line Interface (CLI)
If the web interface is inaccessible but physical access to the system is still possible, the boot environment can be changed at the welcome screen of the CLI.
Reboot the system. When the welcome screen appears, press the key that corresponds with the option Boot Environments. In the image below, the key to select the Boot Environments option is 7.
The Boot Environments options does not appear when no additional boot environments are present.
After selecting the Boot Environment option, choose the new boot environment to activate. Press the corresponding key for the Active: option. In the picture below, the key is 2.
Press the key to cycle through existing boot environments. When the desired boot environment is selected, press Backspace to return to the welcome menu. Then, press 4 to reboot the system. The selected boot environment is used when the system reboots.