Does virtualisation really beat a fleet of mainframes?

While mainframe defectors like the TTX, the New York Stock Exchange, and Meritz Financial Information Services tout their reasons for migrating off big iron onto x86 servers, mainframe proponents say there are plenty of reasons not to.

Joe Clabby, who leads the analyst firm Clabby Analytics, said the trend off mainframes and onto x86 servers running virtualisation is actually a step backward.

"PCs are not mainframes, and VMware is nowhere near mainframes from an advanced virtualisation and provisioning perspective," he said. "Mainframes are so much more advanced than VMware that it may take that customer 10 years to get what they have now in virtualisation, automatic provisioning and workload management."

Not surprisingly, mainframe kingpin IBM concurs. "It's like comparing a Mini Cooper to a tractor-trailer truck. Sure, the Mini Cooper is more efficient, but if you are moving out of your house, which one is better to have? Which one will be able to carry that baby-grand piano? And how many trips would you need to do the same job with the Mini Cooper?" said Jim Porell, IBM's distinguished engineer and chief architect for IBM System z software.

IBM's generic answer: The System z10 EC mainframe can replace 1,500 x86 servers, and the IBM System z10 BC has the capacity of up to 232 x86 servers.

Still, some companies are continue to migrate from mainframes, citing lower costs.

TTX chooses migration from mainframes
Chicago-based TTX Co. is something of a poster child for such migration. It will retire its IBM mainframes by 2010 and plans to re-write all its mainframe apps, add features, and run them on a mix of Hewlett-Packard Co. DL 580 G4 servers and HP blade servers, along with VMware ESX version 3.5 virtual machines and Windows.

"We have essentially re-created the mainframe experience on a less expensive platform with more capabilities," said Rob Zelinka, TTX's director of infrastructure. "It is a significant change in footprint and it lowers operational expenses because it lowers power, cooling, and floor space; we are down to just two rows of servers compared to the five rows of server racks we had before."

Clabby said while acquisition costs of x86 and virtualisation are lower compared with mainframes, he doubts there will be long-term savings from using "a less-secure, less reliable" computing model.

"They're buying into a broken model of computing known as distributed computing, where management costs are way out of control and where they'll scale by adding more blades, racks or servers -- all running at maybe 40% of utilisation because they have to leave headroom for their application and database servers to handle peak workloads," Clabby said.

"Start adding up all the networking costs, the tons of people they need to manage the distributed environment they're putting in place, the multiple security licenses, the business continuity measures they'll have to put in place -- they're out of their minds if they think they're going to save big money doing this," he added.

IBM's Porell appears less absolutist about mainframes, and says a mixed environment of x86 servers, virtual machines and mainframes works well. But he agrees that moving off the mainframe entirely and onto x86 servers is a step down, because mainframes are designed to "run every workload known to man and multiple workloads at once using a superior operations model."

"The mainframe is the Mercedes Benz of computing; it has everything you need already in it. The PC is a bare-bones system that requires you to buy all the software and tools you need to run your applications," Porell said.

Mainframe "myths" lead to desertion
VMware influenced TTX's decision, Zelinka said. "The management, in many cases, is easier and more robust, but most importantly, costs less from an operational perspective -- plus, the annual maintenance with VMware is a fraction of what IBM charges for a mainframe," Zelinka said.

Software for x86 servers such as HP's Insight Manager also impressed Zelinka because it offered deeper visual granularity and allows TTX to run a lights-out data center, whereas its older IBM mainframes required a full-time staffer to "look at screens all day."

But IBM's Porell said the idea that mainframes need to be babysat is a myth. "I have been managing mainframe processors from home since the mid-1980s … and we have customers with data centers in Atlanta that are running them from New York and Florida. They do all of their software upgrades and maintenance remotely," Porell said.

The idea that all mainframes are inefficient, have expensive software licensing, and exorbitant maintenance costs also overshadow the mainframe, but Porell said those stigmas are not true of modern mainframes.

"Depending on which generation mainframe, the cost of software, the power and the floor space differs. People who give up on mainframes probably use older systems, but when you look at the cost and time it takes to re-write all the apps for [x86 servers], moving them over to a more modern mainframe probably costs less," Porell said.

He acknowledged that the mainframe has suffered because Java developers haven't written for it. "It isn't that people are giving up on mainframes … it's that programmers today use PCs as their platform to deploy applications, and fewer are developing for the mainframe," he said. "That is something we are working on now: getting programmers to deploy apps for both."

Still, at the end of the day, Porell said there are five priorities to consider when it comes to whether to stay on the mainframe or not; business resiliency, security, capacity management, business process integration and storage needs. All of these are the mainframe's wheelhouse.