You can use the ADRDSSU util which allows you to dump or back-up DASD datasets onto sequential files on DASD or tape volumes. You can use INCLUDE or EXCLUDE statements to filter out the datasets you want backed up.
I believe ADRDSSU is available under DFDSS (Data Facility Data Set Services) for z/OS. But I may be wrong. Check with your site admin to confirm that this facility is available at your site.
I have attached a sample JCL for backing up/restoring datasets.