If a failure occurs, you can quickly fall back to the original boot environment with an activation and reboot. You could fall back to the original boot environment for the following reasons:
If the new boot environment cannot be booted
If the new environment boots but does not work completely
If you are not satisfied with the results
The use of fallback takes only the time to reboot the system, which is much quicker than backing up and restoring the original. The new boot environment that failed to boot is preserved. The failure can then be analyzed. You can only fall back to the boot environment that was used by luactivate to activate the new boot environment.
You fall back to the previous boot environment the following ways:
If the new boot environment boots successfully, but you are not happy with the results, you run the luactivate command with the name of the previous boot environment and reboot.
If the new boot environment does not boot, you boot the fallback boot environment in single-user mode and run the luactivate command and reboot.
If you cannot boot in single-user mode, do one of the following:
Boot from DVD or CD media or a net installation image.
Mount the root (/) file system on the fallback boot environment.
Run the luactivate command and reboot.
For procedures to fall back, see Failure Recovery: Falling Back to the Original Boot Environment (Command-Line Interface).
Figure 30–9 shows the switch that is made when you reboot to fallback.