Mark Anzani, vice president of System z hardware products at IBM, reckons that despite their massive power demands mainframes are a greener alternative to distributed server environments. In an exclusive interview with GBN he argues that mainframes are more energy efficient than rival datacentre technologies and outlines how IBM plans to improve their green credentials still further.
GBN: As head of hardware development in the US for IBM's mainframe technologies how important is energy efficiency when you are running development projects?
Mark Anzani: In the past year I've received more questions from customers than ever before on energy efficiency. Purchasers are really being driven by the economic and environmental need to cut energy demands. The other big issue is just the simple practicality of getting power and cooling capabilities into a datacentre. There are customers with datacentres in major cities like New York and London who have plenty of floor space sitting unused just because they can’t get enough power into the building.
And you’d argue mainframes can help with this problem?
When you hit a certain workload the larger servers or mainframe environments are more energy efficient on an [energy used per] unit of work basis than multiple servers working together. We took a look at the energy used for the same workload when run on distributed four-way Unix servers and on a z9 mainframe machine. The energy consumption of the z9 was ten times less.
Why is this?
One of the fundamental characteristics of mainframes is that they are good at running multiple workloads simultaneously and that they can deliver high utilisation rates. In contrast distributed servers tend to run at a very low utilisation rate. They are improving because of virtualisation but they are still very low.
What is it about the mainframe that makes it more efficient?
It is a very rough analogy but if you've got a trucking company that needs to ferry packages from one point to another it is more efficient to put 1,000 packages in one large truck than each individual package in its own mini cooper. The same priniciples apply between the mainframe and distributed environment – it requires less power to complete workloads when the whole workload is done in the same place.
If this is the case why do distributed server environments remain so popular?
Platform selection always starts at an application level and the person making the decision tends to go with what they are familiar with. That means they tend to start with Unix servers, but then as the workload increases they prefer to just add more servers. A lot of [the reliance on distributed servers] tends to be psychological.
Will that change?
I'd argue that now mainframes have better technology for application aggregation it is far easier to migrate these distributed server environments onto a mainframe that is more efficient in terms of both support and energy consumption. It is not that it is the sole issue but energy efficiency is a big part of the strong economic case for server consolidation.
Mainframes may be able to undertake a lot of work but they still have a very large energy footprint. What is IBM doing to lower the energy requirements of its mainframes?
We are constantly focusing on the passive power of the chips. We are looking at dynamic power management systems that allow you to automatically cut power to areas of the chips when those areas are not being used. It allows you to manage the total power demands far better. You'll see aspects of this technology in a couple of years – maybe earlier.
Where else can you make improvements?
Efficient management of data is another area we are focusing on. There are increasingly sophisticated technologies out there for compressing data so that the physical storage space required is lowered. Using that technology effectively is a good way of reducing the amount of storage kit you need and that helps your overall energy demands.
You may be able to cut the energy mainframes use but a lot of energy is still required to cool the machines. Are there any plans to tackle cooling requirements?
It's true that much of the power in a datacentre is used removing heat. We have already developed energy efficient frames that use chilled water to remove heat from server racks and we'll see those cooling techniques adapted for mainframe machines in the near future.
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