News

posted on 22 April 2008 17:45

Hitachi Data Systems has announced the world’s most eco-friendly and power-efficient data centre - but it hasn't been built yet and is a Hitachi showcase, HDS only supplying the storage, it not being an HDS data centre.

Hitachi has a massive 387,459 square meter data centre in Yokohama, Japan. It is adding a tiny wing to it, about a thirty sixth of its size, at 10,782 square meters, to show the world what it can do rto aise the power efficiency rating of a data centre.

The idea is to use the Green Grid's Power Usage Effectiveness (PUE) rating which divides the total power delivered to a data centre by the power used by the IT equipment in it. The theoretical ideal is 1.0 but, since power is needed for heating, cooling, air-conditioning, battery backup UPS kit, and as power is lost in transmission and when it is converted, many existing data centres have a PUE rating of 3 according to the Green Grid data centre efficiency consortium. Hitachi reckons it can reach 1.6 with the green showcase wing.

Hitachi's CTO, Hu Yoshida, blogs that this will be a "Tier IV (data centre which) is the highest tier which supplies active/active redundant power supplies and supports less than 0.4 hours of annual IT down time due to site failure."

The new data centre annexe will use all Hitachi equipment: servers; networking gear; and storage. It will also have water-cooled racks and efficient UPS and power supply converters to minimise power losses.

Since it hasn't been built yet the actual storage configuration is unknown.

The HDS announcement says, regarding its virtualising USP-V and USP-M storage arrays: "the combination of Hitachi Dynamic Provisioning and virtualisation provide significant improvements in capacity utilization, (and) also lowers customers’ power and cooling consumption rates. Organisations therefore require fewer storage devices and ultimately, less electricity and space, which results in immediate improvements to overall storage economics."

However, whether you use virtualising and thinly provisioned storage arrays or not a data centre's PUE rating will not change. The PUE is not measuring the environmental efficiency of IT equipment in a data centre at all, only the efficiency of the data centre infrastructure in transmitting the total power delivered to the data centre to the IT equipment within it.

So the use of thinly provisioned UPS storage or power-down capable SMS/WMS storage is irrelevant as far as a data centre PUE rating is concerned. Both will reduce the data centre's need for power, which is a good thing, environmentally-speaking, but that doesn't count towards its PUE rating. That's one of the limiting aspects of a PUE rating.

The PUE rating on its own isn't enough to indicate whether a data centre is green or not.

Also, by adding a new wing to its existing Yokohama data centre, Hitachi is increasing its carbon footprint and therefore worsening its environmental record. There is nothing in the announcement about existing equipment being retired. Green is as green does.

^{[Paul Roberts, news editor.]}