Nasuni this week said it has closed a new round of funding, with this round led by a strategic vendor the company said it could not name.

The new Series C funding round of $20 million brings total funding in Nasuni to $43 million, said Andres Rodriguez, CEO of the Natick, Mass.-based storage vendor.

Nasuni develops software that lets solution providers tie local storage hardware and virtual storage appliances in remote and branch offices with public or private storage clouds to protect data in the cloud while providing full local performance and a 100 percent availability guarantee.

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The company's appliances, based on that software, connect local storage to cloud-storage offerings such as Amazon Web Services, AT&T, Nirvanix and Windows Azure to offer Storage-as-a-Service to customers and provide channel partners with recurring revenue opportunities.

Nasuni this Summer added unified NAS-SAN capabilities to its offering.

Rodriguez declined to say who the new strategic investor is. "But next year, it will be obvious," he said.

What may become "obvious" could be tied to a future OEM agreement. Rodriguez said Nasuni has not yet signed agreements to OEM its software with a storage hardware vendor, but that will likely change.

"I believe an OEM agreement is important for any company who wants to provide one level of enterprise-class storage partners can take to anywhere in the world," he said.

The ability to tie a customer's storage infrastructure with a cloud of their choosing is important, but not all that common, Rodriguez said.

"Amazon and Rackspace have no interest in working in traditional data centers," he said. "They want to move the entire data center to them. That's OK for SMBs, but not for enterprise customers."

Rodriguez also said to not count on large storage vendors to facilitate business' move to cloud storage. "Large vendors like NetApp and EMC struggle to do the low-margin business of the cloud," he said.

Nasuni's customers can put the vendor's appliance in a data center, power it up, and access high-performance capacity on their existing storage while leveraging the Internet and a cloud for larger capacity, Rodriguez said. "The control is all done via Nasuni," he said. "We have no visibility to the data, but we do control it. All data is stored in the cloud. But copies are kept on local storage for performance."

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Nasuni, which this week said its third-quarter bookings grew 250 percent over last year's third quarter and that 100 percent of its enterprise customers renewed contracts, uses a channel-only model to reach customers.

One of its newest channel partners, Scottsdale, Ariz.-based Thin Client Computing, is talking to its virtual desktop and thin-client customers about how Nasuni fits in their infrastructure.

Steve Greenberg, founder and principal architect for Thin Client Computing, said his company has yet to sign a Nasuni deal with customers, but he expects such deals to be closed soon.

"The sweet spot is customers with multiple locations," Greenberg said. "They can save a lot of cost in terms of storage footprint and collaboration tools. Just the idea of having a folder via Nasuni where people can share files is big."

Greenberg said Nasuni has made it clear there are two types of storage, including primary storage such as databases, emails and SharePoint, where performance is important, and general-user data, files and folders, which can be replicated to the cloud and made available for sharing and remote access.

As a result, Greenberg said he has overcome his reluctance to embrace cloud storage.

"I'm a server hugger," he said. "I believe a customer should keep control of its assets. But Nasuni is changing my view."