Making the case for the mainframe

The mainframe endures, despite its many critics. How can an idea from the 1950s thrive half a century later?

Tesco's current assessment of whether to migrate applications onto the mainframe to simplify IT operations and reduce its carbon footprint has sparked debate as to whether the move may signal a possible resurgence of the technology.

The review by the UK's largest retailer was instigated in response to a series of 'green' pledges made by chairman Terry Leahy at the start of the year. One of those pledges was a promise to halve the company's 4.1 million tonne carbon footprint, about four percent of it generated by IT, by 2020.

While doing the evaluation, Tesco discovered that Wintel platforms accounted for 29 percent of this IT carbon footprint, compared with three percent for mainframes and 18 percent for storage systems. As a result, the firm decided to step up its consolidation and virtualisation efforts in the x86-based server domain as an interim step, although it plans to make a decision about more permanent re-platforming by the end of 2009. The goal is to deploy virtualisation as standard in its Wintel server estate and to cut the number of such servers from about 1,500 to between 150 and 300.

So what makes the mainframe environmentally appealing and more 'green' than the Wintel or Unix alternatives? John Phelps, a research vice president at Gartner, says that despite much talk about corporate social responsibility goals, the bottom line counts for more than the environment.

Keeping costs down
Energy bills and lack of datacentre space are both areas that can be helped by efficiency. "One way of reducing energy costs is to ensure that equipment is more efficient and to introduce things like modern uninterruptible power supply systems," says Phelps. "Another is to reduce the load for power and cooling by utilising servers more fully, as a server uses almost the same energy whether it's running at 20 percent or 100 percent capacity."

Un-virtualised x86 servers in siloes typically utilise between eight and 13 percent of their resources at any given time. Unix systems manage between 25 and 30 percent; mainframes as high as 80 to 90 percent.

According to Doug Neilson, a systems consultant at IBM's systems and technology group, the average high-end Z10 mainframe consumes about 15Kw of energy, while a large Intel server consumes about 1Kw. He claims that introducing a mainframe can result in consolidation ratios of up to 30 (unvirtualised) x86 software licences to one (mainframe licence) as well as savings of up to 85 percent in power and cooling costs and the same in floor space because more transactions are undertaken per watt.

But Roy Illsley, a senior research analyst at the Butler Group, points out the lack of reliable, independent figures available in this area. "The issue is whose figures can you believe? The trouble with the whole 'green' debate is that there are no standards you can apply and there are very conflicting views depending on whom you talk to," he says. "It's very difficult to make a judgement because you need independent comparisons based on workload and how you're using it and to work out things like energy savings and carbon footprint from that."

Another area to consider is the energy used in the manufacture of systems, both in the wider supply chain and in disposal. "It's an area that isn't really considered today, but it should be. Mainframes may take more energy to make but they last a long time, while distributed systems may take less but probably only have a three-year lifespan," says Illsley.

Nonetheless, Phelps believes the mainframe provides a "very good" environmental footprint when used as a consolidation tool. "The gold standard for utilisation is the mainframe. Because it runs diverse workloads on one system, you can drive utilisation rates up and you need fewer servers to do it so power and cooling demands are reduced. The latest z10 machines also include up to 64 engines and, because there's not much difference between running one or 12, you can increase the number quite dramatically with little environmental impact", he says.

And this ability to handle mixed workloads is an important one. One of the reasons x86 server farms are often uneconomical...

...and wasteful in energy terms is that the boxes tend to be over-provisioned and workloads are not mixed efficiently.

But such factors are not the only reason that organisations are starting to show renewed interest in the mainframe. One of the most significant drivers behind IBM's 34 percent increase in MIPS last year — the company measures the market by total processing capacity expressed in millions of instructions a second — and a 32 percent rise in mainframe revenues over the same period, year-on-year, was the recent introduction of various speciality engines to run Linux and Java. Another driver is the ability to run IBM's DB2 database on the same machine as enterprise applications such as SAP or Oracle sitting on its WebSphere application server.

According to Phelps, the move has led to between 60 to 70 percent of all net new MIPS shipped over the past few years being used for consolidated application workloads that did not exist on the mainframe 20 years ago, with Linux now accounting for 11 percent of all MIPS installed worldwide.

The overall market itself, however, has grown on average by 15 to 20 percent in net new MIPS terms over the same time period. This is because, although the speciality engines are separately billable and cost about $125,000 each, they are not included in regular capacity-based licensing fees, which would add to costs significantly.

"This has allowed IBM to move into new areas without causing pricing problems in relation to legacy systems. So the speciality engines enable organisations to enhance their capabilities or run new workloads at a good price, which is part of a wider total cost of ownership [TCO] argument," says Phelps. Factors to be taken into account here include low administration costs due to the better reliability, availability and security of mainframes in comparison with rival platforms. As a result, he advises: "It's important not just to look at acquisition costs, but also TCO over a three- to five-year timescale."

Market dominance
However, while large enterprises generally have no problems in this context, the same is not true of smaller organisations as even the relatively low-cost speciality engines still account for a large chunk of their IT budget. Another issue is that, to generate TCO savings, it would be necessary to consolidate on average between 40 and 50 Linux boxes onto the mainframe to make it worthwhile.

To make matters worse, software pricing is tiered and works out proportionately much more expensive at the lower end of the MIPS spectrum than at the high end. And a further challenge at the applications level is that not only is the mainframe far from the first port ISVs think of when building new packages, but there is also no significant partner ecosystem to write them in the first place.

This means the market is dominated by a handful of vendors — IBM itself, Computer Associates and BMC — although Phelps indicates that as many as 300 new applications, including middleware, utilities and vertical market packages, did appear last year, which was the first time such growth had occurred for some time.

Nevertheless, says Butler Group's Illsley, the mainframe sector is "very skewed" by IBM's almost total dominance. "The market needs some medium-sized applications vendors to represent stability for CIOs and I doubt that many of them would want to put all of their eggs in the mainframe basket," Illsley explains.

A further downside is that, while support for environments such as Linux, Java and IBM's WebSphere application server means that skills in these areas are now portable, organisations may...

...find it difficult to recruit expertise in fields such as legacy application management and systems-management disciplines such as capacity planning.

Marc Lillycrop, managing director of consultancy Arcati, indicates that the skills shortage may be somewhat "overstated" today. However, he warns that in the future there is "potentially always going to be a problem with older skills as there aren't enough education processes around to replenish them and people aren't necessarily rushing to go into it".

IBM has been attempting to rectify this situation since 2004, by hooking up with academic establishments worldwide as part of its Academic Initiative. The vendor now has 400 colleges and universities actively teaching and developing mainframe courses and accredited certificates, which has led to almost 50,000 students being trained in this area. But existing issues mean the mainframe is unlikely to take over the world again any time soon, as much as IBM's Neilson might like to convince the market that "the trend towards distributed systems went too far and is now swinging back towards centralisation".

While Phelps acknowledges that 93 percent of those surveyed at a recent Gartner conference indicated they were consolidating or planned to consolidate their x86 servers, mainframes were not the only environment under consideration, with high-end Unix boxes also being in play. Therefore, although the market is growing, such growth is likely to remain "slow and steady" rather than meteoric, although green IT considerations and "more focus on things like SAP may result in some up-tick", Phelps says.

Balancing out
While some sites are sticking with mainframes or becoming first-time users, others are migrating away, evening the picture out. As Lillycrop explains: "There's continued relatively healthy growth at the top end where larger users are tied to the platform due to a heavy investment in resources and proprietary applications, but lower down the scale where people are less entrenched, it's much more imbalanced and can go either way."

The downside for the mainframe here is that customers at this level often prefer an environment that costs less upfront in hardware and software terms — a factor that can act as a strong deterrent — particularly as there is a widespread perception at the upper management level that the mainframe is old-fashioned and dying. Moreover, the growth in new systems adoption is coming more from developing economies such as India, China and Eastern Europe than western countries such as the UK, where the mainframes' heartlands remain financial services companies, large retailers, government and defence.

That is not to say that the mainframe should be written off any time soon. "It's the top end of the mid-market up to large multinationals, those that have traditionally used AS/400s (now called iSeries) and Unix, where it's going to be interesting. The mainframe is coming down to that space and midrange servers are going up, so that's where the battle for hearts and minds is likely to be," concludes Illsley.