Email storage startup Sonian has taken a follow-on sum of $8 million to augment its Series C, which now totals $21.6 million.

The cash comes from existing investors OpenView Venture Partners, Summerhill Venture Partners, and Prism Venture Partners.

The company writes via email that the money will be used on a new product, DiscoverStor, which will have its official launch sometime in the next two and a half months. DiscoverStor is an email archiving and reference product that includes new file types and advanced analytics. Such products are needed in the enterprise, where email storage is important for regulatory compliance.

“Sonian is well poised to continue its remarkable growth trajectory, thanks to our innovative approach and long-standing expertise moving corporate data to a secure cloud archive and illuminating that data with fast and accurate search,” said Jeff Dickerson, CEO of Sonian, in a statement on the news.

“We have a lofty goal to take all human-generated data, from emails and documents to CAD drawings and beyond, and make it searchable — and therefore actionable — within a cloud architecture. The continued support from our investment and reseller partners will hasten our ability to deliver on this vision and create the world’s first true dedicated information discovery cloud.”

Sonian was founded in 2007 and is based in Newton, Mass.