Sun Microsystems is joining in the pricing pig pile atop Red Hat, the leading Linux software company.

Sun said last week that it will join the likes of Oracle and Microsoft to challenge Red Hat’s open source dominance. Sun’s strategy includes support for its free download of Solaris 10, a Unix-based operating system, that will cost 40 percent to 50 percent less than comparable support for Red Hat’s Linux operating system.

Red Hat, the largest Linux distributor, has faced other price competition of late, notably an October move by database software company Oracle. In November, operating system giant Microsoft aligned itself with Novell, a rival Linux distributor to Red Hat.

Sun’s Solaris annual support contracts range from $240 to $1,180 for one- or two-socket x86 servers, depending on whether the buyer chooses the “basic” or “premium” plan. Red Hat Linux ES basic goes for $349 per year, per system, and Red Hat Linux AS premium costs $2,499.

A Red Hat spokesman said the Sun announcement was more validation of the shift to open source that’s underway in the enterprise.

“Over the years the trend has very clearly been for customers to migrate from costly, proprietary systems to open source. This has caused our competitors to take note,” said Leigh Day, Director of Global Corporate Communications

Red Hat CEO Matthew Szulik has said his company would not lower its prices to match competitors such as Oracle.

“I see this as more of a volume play,” said Jonathan Eunice, founder of technology research firm Illuminata, who read the news as a move by Sun to get more people to choose Solaris instead of Red Hat Linux.

But Sun is competing on value -- not just price -- said Rich Green, executive vice president of Sun’s software division.

“We wouldn’t be working at a loss, I assure you,” Green said. “The scale and volume that we have allows us to place bets on what we would need to support them.”

Green also dismissed published reports that Sun was considering releasing Solaris under the GNU General Public License Version 3, clearing the way for integrations with other open source projects.

“It just ain’t so,” Green wrote on his blog on Wednesday.

Red Hat’s options are to lower prices and lose margin or to maintain pricing and lose customers, said Merv Adrian, an analyst at Forrester Research.

“Red Hat ... lowered the cost of acquisition of the software and increased the cost of support,” Adrian said. “Now it’s a case of ‘Turnabout is fair play.’”