Faculty have continuous online access to their course sites for the current academic year and the two previous academic years, and always have the option to create and store their own course backup files while they have online access to these course site. If you want to use the content from one of your previous courses in a new course site and you already have access to your own course backup files (or have access to the original course sites where you can create the backup files), you can use the detailed step-by-step backup & restore procedure provided in the onCourse help site (you will first need to login to onCourse).
Note that access to a backup file of the original course is required to complete the procedure mentioned above. After this time period of up to three academic years, all the old course sites are backed up by the onCourse staff and taken offline. These backed-up course sites can then only be accessed by the onCourse staff. To request retrieval of an old course site and assistance with course content transfers you can contact the staff with information about the semester and year that you taught the course.