November 4, 2005

MapFS makes its debut

Author: Stephen Feller

After nearly two years, Levanta is making an effort to bring the MapFS kernel module to a wider audience. MapFS is part of the core software for Levanta's Intrepid M management appliance, a system for provisioning, deploying, and managing Linux servers.

The software has been available under the GNU General Public License (GPL) since its inception, but the company has stepped up efforts to publicize the software by posting it to SourceForge this Monday, and sending out a press release touting the availability of the virtual file system software.

Although not all of the software that runs the Intrepid is open source, MapFS is a loadable kernel module for Linux, and is required to be made available to customers under the GPL. David Dennis, Levanta's director of products, said that the move is an effort to give back to the open source community, and see where other developers can take the software.

"We felt we had enough functionality developed above and beyond what MapFS does that it's not a competitive threat to us to hand it back out to the open source community," Dennis said. "People might come up with new ideas, directions or improvements that we hadn't thought of. They may even come up with ways to make it better that we may incorporate back into the way we use it."

By giving back, the company is looking to expand the possibilities of what MapFS is capable of doing and is used for, and build a viable developer community around the module. "We made the decision that, after it had been out for two years, now was a good time for us to widely distribute it," Dennis said.

Designed to simplify the interaction and use of a Linux network, the MapFS module specifically offers "optimistic copy and write capabilities," allowing users to share a single virtual file system that appears to be read-only, but allows users to save changes to files by writing changes to their own systems rather than the original files.

With a new version of the Intrepid appliance planned for next April, Levanta has yet to determine exactly how often internal snapshots of MapFS will be synched with the code on SourceForge.

According to MapFS co-creator Nate Stahl, the code released on SourceForge Monday is the latest version of the software, and even is more recent than the version Levanta customers have received. While they have not yet figured out how often to update the publicly available source code, Stahl said "they should mirror each other" and each should be updated with some frequency.

"I don't think it's in our interest to keep them wildly deviant, that would be counterproductive," Dennis said. "If the versions are too different then that process isn't going to work." The idea of releasing the code, he said, is to have a group, rather than just the company, pushing development of MapFS forward.

Although other open source projects have similar functionality to MapFS, Dennis said MapFS is the only project working at the file level of a network system. He said this could be what attracts other companies and developers to take a look at Levanta's software.

Dennis pointed to a recent proposal by Red Hat on stateless Linux in Fedora, which is a direction similar to that of MapFS -- and both Dennis and Stahl are hoping Red Hat and the Fedora Project will adopt MapFS. "We'd love it if developers would take a look at it," Dennis said.

One possibility Dennis and Stahl mentioned is a set-up that can run off a live CD. According to Stahl, they would like to see users have the ability to change things that run off a CD, and MapFS would make it easier to facilitate such a use. He said that by populating the view so that it refers to all the files on the CD, and setting up a temp directory to be used for the copy and write target, users would be able to modify any of the files on the file system.

The software has only been out for a few days, so it's too soon to say what kind of changes the open source community might make to MapFS, or whether the project will catch on at all. Still, Dennis and Stahl said they are eager to see what might happen, and there's little concern that MapFS will assist competitors. Dennis said it would take a couple of years for another company to reverse engineer all of Levanta's work based on only the open source MapFS.

"In some ways it would be a flattering testimony if we had a competitor who wanted to use it for commercial purposes," Dennis said. And although they're curious to see if other like-minded companies with similar goals of balancing proprietary products with truly open source ones, the difference between an imitation of Levanta's products and the real thing would retain the Levanta customer base, he said. Then added, "I don't think we're too worried about it."


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