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Issue Date: June 2007

Less blanks please

June 2007
Tim Stammers

Without IT, the airline industry would be a fraction of the size that it is now, and the term jet-set would still have currency as a label for the rich and permanently sun-tanned.

Without IT, the airline industry would be a fraction of the size that it is now, and the term jet-set would still have currency as a label for the rich and permanently sun-tanned.
This is not just because computers have been so instrumental in both the design and manufacture of jet engines and aeroplanes. It is also because of computerised booking systems, which have hugely increased the efficiency with which airlines fill the seats on their jets. Bums-on-seats is the order of the day for airlines, because empty seats cost virtually as much to lift into the sky as those that are occupied.
But while the IT industry has helped airlines reach nearly perfect load factors, it has not done such a great job for its own products. Customers pay good money to buy and power ever-increasing amounts of server and storage gear, and then usually see only a fraction of that processing and storage capacity put to work.
In some cases, the utilisation rates are pitifully low. Processor virtualisation technology is doing a lot to put this right for Windows and Linux servers. Until now the limited partitioning on those platforms has forced businesses to run critical applications on separate servers, and the processor utilisation rate for un-virtualised Windows and Linux servers is estimated to be typically around 5% to 10%.
The situation in storage is not hugely better. The emergence of storage networks at the beginning of this decade boosted disk utilisation rates, by allowing arrays to share out their disk capacity across many more servers. Another boost came from SRM software, which finally gave businesses a practicable way of discovering what storage capacity they own, and what data is being stored on it.
But even now storage utilisation rates in average businesses are estimated to be around only 30% to 40%. Of course there is a need for headroom, but not so much that there is twice as much empty space as used space. Especially not on storage arrays that can carry dollar price tags running into seven figures, or up to around $40 000 per terabyte.
Not that the issue is limited to the upfront purchase price of hardware. Because a sparsely loaded disk array spins the same number of disks as one that is fully loaded, it consumes almost as much power and so generates very nearly as much heat. For the growing number of customers that are running out of electricity and cooling capacity in their data centres, that is a waste of an increasingly precious resource.
One way to lower both electricity consumption and upfront costs is to use fewer Fibre Channel disks inside the arrays, and cheaper, high capacity, slower spinning ATA drives. According to EMC, a gigabyte of capacity on a low cost ATA-style [sic - 'ATA-style' not 'ATA'] drive consumes eight times less power than it does on the fastest and smallest FC drives.
So the one-time arch-promoter of information lifecycle management is telling its customers that they can lessen their power and cooling problems by setting up storage tiers based on different classes of disk drive. If this is all that ILM ever was beyond the marketing hype, it is at least still relevant.
Two software technologies that will apply to any type of disk drive are data de-duplication, and thin provisioning. De-duplication does exactly what its name suggests, and when applied to some types of data such as backups it can reduce data volumes by sizeable factors, sometimes as much as a few hundred to one. In itself that might not be considered to be increasing disk utilisation rates, but it does reduce the amount of disk that customers need to install and power.
Thin provisioning allows customers to virtualise and so hugely reduce the amount of empty or unused storage headroom that they need to allocate to applications. For some it has already led to a doubling of utilisation rates. Like data de-duplication, thin provisioning will be coming to an array near you, and soon.
Will all this make businesses feel that they are at last getting enough from their hardware, or reduce their carbon footprints sufficiently to head off catastrophic global warming? That question cannot be answered yet. But certainly applications running on servers and bytes stored on data centre disk arrays are set to suffer the same squeeze that the average economy class flier has been feeling for some years.

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