As you know that having just CMS DB backup won't suffice to bring the system up in case of disaster. For that you will also need Filestore backup.
I believe the answer to your question would be:
1. Take a DB backup using a DB backup stategy. 2. Use CCM to copy datasource from your present DB (as source) to another backup DB (as destination) 3. Use IW to create biar (not always a very reliable backup strategy).
If you use copy datasource option you also have option and advantage of copying the source cms db to any other db like Oracle mySQL MSSQL Sybase.(irrespective of what is the source db)