When you save a large group of libraries, you should place your server in a restricted state. This ensures that the server saves all of the important objects. For example, if subsystem QSNADS or directory shadowing is active, the server does not save files whose names begin with QAO in library QUSRSYS. The QAO* files in library QUSRSYS are very important files. If the server does not save the QAO* files, you should end the QSNADS subsystem (End Subsystem (ENDSBS) command or End Directory Shadow System (ENDDIRSHD) command). Then you can save the QAO* files.
Be sure that you regularly save the QGPL library and the QUSRSYS library. These IBM-supplied libraries contain information that is important to your server and it changes regularly.