Little did anyone realize that a partnership between IBM and Arsenal Digital Solutions would lead to an even bigger deal. Instead of being a partner, Arsenal will soon become part of Big Blue.

Seeking to broaden its data services suite, IBM said Thursday that it was acquiring the Cary-based data storage and services firm. Financial details were not disclosed.

“We preferred Arsenal to other companies,” said Mike Riegel, vice president of information protection services for IBM. Riegel is based in the Triangle. “We have had a partnership with them for several months. This deal is an outgrowth of the success we had as partners.”

Arsenal and its 100 employees will become part of IBM’s Global Services unit. While the privately held firm doesn’t disclose its finances, its impact for IBM could be far larger than its size indicates. Arsenal has more than 3,400 customers, operates on five continents and delivers proprietary technology for data storage and recovery in a $17 billion a year market segment that is growing 30 percent a year, according to Riegel.

IBM already is a big player in data hosting with some 150 centers around the world. But the services group wanted to add more services, such as on-demand capability and improved security. Arsenal provides both.

“Customers large and small are simply overwhelmed by the growing amount of data they have to manage,” Riegel explained. “As much as 60 percent of data is outside the corporate headquarters, from remote offices to laptops. It’s an enormous challenge to manage it all, and most importantly it must be protected.

“IBM is very strong in business continuity. We absolutely wanted to acquire an on-demand data protection firm,” he added. “Arsenal fits perfectly with our continuity services

“What excites us about Arsenal is that it’s obviously growing very fast and has been recognized with numerous awards across the industry.”

Arsenal, which was founded in 1998, decided to accept the IBM offer after reviewing many alternatives, according to Chief Marketing Officer Brian Reagan.

“When we thought about what would be the best match for our shareholders and employees, we felt that was IBM,” Reagan said. “They provide us with the market reach on a global basis, a global brand, and sales support that we could achieve on our own.

“We certainly as a private company weighed all our options,” he added. “We decided this deal was the right one at the right time to accelerate our growth plans.”

Arsenal, which Private Equity Wire reports has raised some $80 million in venture capital, had options for growth such as going public or being acquired by someone else. When asked if other companies made bids for Arsenal, Reagan declined comment.