Getae and Dacians? Are they the same? Or is this unknowable?

[Rumo]

I'd like to share also a fragment from Guy Halsall's aforementioned book about identities and Goths:

• In a late antique situation who, within a mobile and fluid group of Goths could gainsay the claim of a Roman provincial to have had a Gothic grandfather?
  The fact that individuals possess a series of identities, which we might think of as ethnic, and can order and reorder them in terms of importance, further facilitates such strategies. There were members of numerous ethnic groups within Theoderic’s Ostrogoths. Here people had been accepted as Gothic despite additional identities.
  

There's a footnote referencing Herwig Wolfram's History of the Goths (1988), p. 300-2, where we find a poly-ethnic "Ostrogothic people" including Roman but also "Rugian, Herulian, Scirian, Turcilingian as well as Suevic, Sarmatian and Taifalian elements", with notable individuals having not only Germanic or Roman, but also Alan (Candac) and Celtic (Bacauda) names.