DFM is for reporting and alerting. Operation Manager (and Provisioning and Protection Manager) is another name and modules for DFM. System Manager is GUI for Managing (creating/deleting) Aggregates and Volumes, etc. One other piece of the puzzle is Management Console...performance views/charts of your storage system. If you are running version 3.0.1, it may be time to upgrade! The latest version of DFM is (renamed again) OnCommand Unified Manager Core 5.1. -check the Release notes, System requirements, and Matrix, to see if it fits with your environment. This will be a major upgrade for you.