i dont know what utility to use
Yes, there are multiple utilities that could be used. Your backup should use the same utility others use for backing up libraries on that system.
I suggest you talk with others who have done similar backups on your system and use the same utility process they use. It would be best if all of these were handled n a similar matter.
You should not
create some new way to do this as it is already being done for other pds datasets on your system. System processes (and bgackups ar4e one of them) should be implemented consistently.
Your storage management people may already have model processes defined that you can adapt for this use.