Saving the system
Before you upgrade to a new IBM® i release, you should have a current backup copy of your system.
You do not need to save your system when you have a current backup copy that can be used to recover if a failure occurs. Be sure to keep this backup copy until you save your entire system again. In the IBM i Information Center, the topic Backing up your system contains information about how to perform your save strategy and also the steps to automatically save your entire system.
Note: After you begin to upgrade the Licensed Internal Code
to the next release, the upgrade process must be completed. If you
do not complete the upgrade and you want to return to the previous
release of the operating system, you need to initialize the disks
and reload the system by using the backup tapes that were created
by the GO SAVE command (Option 21) just before you began the upgrade.