Inside Colt's modular co-location datacentre

Over the coming year, ZDNet UK is visiting a variety of datacentres to get a behind-the-scenes look at the range of approaches being taken to meet the demand for data handling. In March, we visited the Colt modular datacentre, which is part of London 3, a much larger legacy Colt site in Welwyn Garden City.

Colt operates 19 datacentres across Europe providing co-location and managed infrastructure services to a variety of businesses.

With around over 1,000 racks spread across 100,000 square feet of IT space, and with an aggregate power drawdown of 33MVA, London 3 is one of Colt's most important datacentres. It represents six percent of the co-location provider's datacentre capacity in Europe, the Middle East and Africa.

For this reason, Colt has chosen the site as a flagship for its new modular hall design for datacentres. The design method is based around minimising the amount of time it takes to construct a datacentre and is being touted by Colt's director of datacentre infrastructure services, Guy Ruddock, as the way of the future.

ZDNet UK visited the site's two modular datacentres, data halls 3 and 4. Pictured is an empty, unracked module.

"In three to five years, if you're building a bespoke datacentre, [you'll] be told you're mad," he said. "There's nobody near us."

The manufacture and testing of the modules is done by Colt, before being shipped to the customer site. Colt has patents pending for its datacentre modules. Ruddock said the company has developed a design of the module that cuts the time it takes for it to be installed on site, but would not elaborate when asked for further details.

See more of the datacentre tour on ZDNet UK.

Ruddock (pictured) told ZDNet UK that the build out for the new halls started in December 2009 and the first customer was in by April 2010.

Colt has based its design techniques on those used on offshore oil and gas platforms to minimise the amount of people it takes to fit a module, Ruddock said. He said that a crew performing on-site installation of a module would number less than 20 and could do it, in ideal circumstances, in between four and six days, although one installation had taken as long as three weeks.

Another design, which Ruddock believes is unique to Colt, has services such as cabling, electricity and fire suppression running through the columns that support the module. This saves on space and, again, cuts the time it takes to cable a module, he said.

The modules are manufactured in Yorkshire, then their infrastructure is tested. They are then broken down into small components that are trucked down to London on the backs of flatbed trucks for reassembly and installation. The installation, transportation and client-site integration process takes less than four months, Ruddock said.

See more of the datacentre tour on ZDNet UK.

Each 5,381-square-foot module can take up to 750KW of IT load, although, if needed, some can go as high as 825KW. Each module can support up to 204 fully sized racks or 254 smaller racks.

The average draw per rack is 4KW, but each rack can suck down as much as 20KW of power, providing dummy servers are positioned either side of it. These dummy server panels ensure separation between hot and cold aisles and keep the power draw stabilised.

Each module has a design life of between 20 and 25 years, according to Colt.

When filled out, each processing aisle (pictured) within the datacentre becomes self-contained. Cold air circulates in at the bottom front grills, and hot air circulates in via the back.

Because the new aisles have a lower power usage effectiveness (PUE) than the legacy hardware on site — 1.21 versus 1.6 — Colt is moving the most power-hungry hardware over in stages, with cloud hardware going in first.

The low PUE is attained by a combination of hot and cold aisle separation, airflow modelling and free-air cooling. The airflow modelling is done via a computational fluid dynamics program, which orchestrates the positioning of each rack according to power consumption to assure a smooth air path throughout the module.

When touring the module, ZDNet UK saw IBM blades, IBM system storage and Cisco networking. Ruddock said any hardware that can be racked can be supported, as Colt acts as a co-location provider.

See more of the datacentre tour on ZDNet UK.

Each of the modules ZDNet UK saw were stacked on top of one another inside Colt's 100,000-square-foot warehouse (pictured).

The exterior of the modules contained the chilling systems, which drew in cold air coming in through grills in the warehouse's shell. The cooling is predominantly achieved through free-air cooling, though there is a direct-expansion cooling system running as backup.

The direct expansion cooling system operates for less than 300 hours a year (12.5 days), according to Ruddock, kicking in when the temperature threshold goes above 27° or when air humidity goes above 70-percent relative humidity.

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