IBM Wednesday said it will consolidate nearly 4,000 PC servers onto mainframes running Linux in a move that will cut US$250 million from the cost of operating its six major data centres.

IBM says the move will save enough energy to power a small town and will reduce by 85 percent the square footage needed to house racks of computers.

The company has 8 million square feet of data centre space, which is the equivalent to 139 football fields. The U.S. sites targeted for server consolidation currently reside on approximately 184,000 square feet, according to IBM.

The company is trying to add yet another chapter to the life of the age old mainframe, which has been left for dead on the side of the information superhighway more than once.

And it is trying to make a statement about the future of distributed computing and IT infrastructure design by tapping into the mainframe's scale, security and virtualization capabilities.

"There are all the altruistic aspects, but IBM is doing this to prove a point they have been trying to make for years," says Dan Olds, principal of the Gabriel Consulting Group. "And that is you can run Linux apps, small apps, the non-traditional mainframe apps on the mainframe by the bushel load and that the usage model will pay off in terms of performance, security and economies related to people costs and facility costs."

But Olds says to be successful IBM will have to win over the non-mainframe user.

"They have to get where a non-mainframe heritage guy, a Unix or x86 guy, is willing to take a look and take it seriously. That is what this is about." He says IBM is being smart with this strategy in that they are converting their own data centres first, which will provide knowledge for IBM and credibility when trying to sell customers on the idea.

"IBM is going to be drinking its own champagne," says Dave Anderson, System z green evangelist for IBM, who said the consolidation focuses on systems that run IBM's business and support 350,000 users. "I think you will see the mainframe make a huge resurgence as people try and run their data centres most efficiently."

IDC last week reported that the IBM mainframe posted its fifth consecutive quarter of revenue growth and outgrew Windows-based servers in 2006 in terms of revenue.

And IBM said earlier this month at its System z Summit that mainframe hardware sales in the fourth quarter of 2006 were the largest it has seen since the fourth quarter of 1998. The company told Big Iron Newsletter that it has roughly 10,000 mainframe installations in the world and reported that in the first quarter of 2007 it had surpassed 11 million aggregated MIPS.

"Nobody has just a mainframe, but it will come back where it makes sense, where you need economy, and where you have enough workload," Anderson says.

IBM's data centre makeover is part of Project Big Green, a commitment IBM made in May to reduce data centre energy consumption for IBM and its clients.

The company will deploy 30 System z9 mainframes running Linux within six data centres to replace 3,900 servers, which will be recycled by IBM Global Asset Recovery Services.

The data centres are located in Poughkeepsie, N.Y., Southbury, Conn., Boulder, Colo., Portsmouth, UK; Osaka, Japan, and Sydney, Australia.

The company is focused mainly on moving workloads generated by WebSphere, SAP and DB2, but will also shift some of its Lotus Notes infrastructure.

The mainframe's z/VM virtualization technology will play a big role in dividing up resources, including processing cycles, networking, storage and memory. With z/VM 5.3, IBM can host hundreds of instances of Linux on a single processor. The z9's Hipersockets technology, a sort of virtual Ethernet, will support communication between virtual servers on a single mainframe. IBM also will take advantage of logical partitioning, which is rated at Level 5, the highest security ranking on the Common Criteria's Evaluation Assurance Level (EAL).

IBM says energy costs represent the bulk of US$250 million in expected savings over five years.

"We are saving over 80% in energy cost by moving from distributed servers to z9 technology," Anderson says. "Not only is there cost in powering IT equipment such as servers and storage, but also infrastructure costs for computer room air conditioning and UPS systems. If you can keep a lean IT infrastructure it helps you have a lean facilities infrastructure."

IBM says it also hopes to reduce licensing costs especially on software that is licensed per processor, and to free up staff to work on projects that will generate revenue.

IBM plans to move its own workloads first but will offer hosting services to customers from the mainframe-based data centres.

And what does IBM have to say to companies such as Google, Yahoo and Microsoft that are building giant data centres, some near hydro-electric power sources, and filling them with racks and racks of servers?

"The model today with distributed servers is unsustainable," Anderson says. "You really want to do more work with less servers and pick energy efficient servers with good reliability and the ability to scale."