Enterprise cloud storage provider Zetta has raised $9 million in its third round of funding, bringing the total funding to $31.5 million and putting the spotlight on the hot cloud-based storage market. Existing investors Foundation Capital and Sigma Partners participated in the round.

Sunnyvale, Calif.-based Zetta, which was founded in 2008, is part of a rapidly expanding group of enterprise cloud storage service providers that are attracting the attention of investors—not to mention enterprises. Zetta focuses in particular on the small and mid-sized business sector. The company’s executive ranks hail from Netscape, VeriSign, Symantec, EMC and Shutterfly, so are well-versed in the importance of data protection and backup.

CEO Ali Jenab told The Wall Street Journal’s All Things D recently how critical it is for small and mid-sized businesses to make data backup a top priority, noting that companies are still creating 15 million tape backups a year.

“We’re not talking the huge guys, but the midsized guys,” Jenab said. “Law firms with 10 to 200 employees, universities, all kinds of smaller health-care companies. We’ve basically built the same kind of high-end infrastructure that the large companies use, and taken it to midmarkets.”

Jenab went on to clarify that the funding round is not a C round, but a continuation of an A round.

Funds from the new round will be used for sales, marketing and product development to help Zetta plunge deeper into the SMB market, according to the company.