Greetings!
2930F switches with 1Gb SFP uplinks can use either SFP transceivers with fiber or Cat5e/Cat6 for VSF links (or even a combination of both, as long as all VSF ports are operating at the same speed). You can use up to 8 ports for each VSF link.
Note that the DACs mentioned are SFP+ (10G) cables and will not function in the SFP (1G) ports on this switch model.