Open source companies to watch

Open source software is a given in most enterprise data centers, so it's not surprising to see the ranks of open source companies and projects swell. It's not just Linux anymore - community-developed software is offering alternatives for everything from databases to application servers to network management to disaster preparedness.

How do you know which open source approach is right for you? We've pulled out a few start-ups that you might not be familiar with, but we think should be on your radar.