Valuation Vs Revenue
So what do their revenue numbers look like? A $2B market cap is pretty big and needs to be justified somehow. Violin is one of the earlier SSD companies, with not a lot to talk about technology-wise except for "it's flash". At least with companies such as SolidFire or Actifio there's a software layer there that adds value (in theory; not wanting to argue the specifics), but I don't see anything in Violin that you couldn't do with a JBOD enclosure and a linux stack with software RAID.
Of course, the last two flash-type acquisitions were massively overpriced as well so perhaps it's just me that's missing the point here.