I need to know the volume of all my datasets in Domo. Is there a way to filter my datasets and sum all their Gb?
If you go in the data center to the data warehouse link, you should be able to see some summary data, including number of rows. It doesn't tell you what it is in terms of gigabytes. In fact, Domo doesn't really mention that in many places. It's usually expressed in terms of rows.
The dataflow history tab displays input and output in gigabyte terms.