Server maker Rackable Systems has joined Sun Microsystems in touting mobile datacentres as the answer to corporate compute capacity, power and cooling needs.

While Sun has been promoting its Project Blackbox since October 2006, Rackable yesterday announced that it has its first customer, an unnamed global ISP. Like Blackbox, Rackable’s Concentro is a modular datacentre in a shipping container that can be transported to supplement crammed server rooms ore act in place of new-build facilities.

The Concentro offers 1200U of rackmount servers, up to 9,600 CPU cores (based on Intel quad-core chips) and up to 3.5 petabytes of storage.

Concentro is designed with today’s electrical power issues in mind and uses Rackable’s DC power-supply system. DC supporters cite lower heat emission and improved reliability while critics point to larger cables, complexity and the cost of retrofitting existing datacentres.

Rackable expects broad appeal from companies seeking mobility, disaster recovery or just additional capacity.

“Folks can sleep a little better knowing we have a container of servers ready to roll out,” said Rackable datacentre solutions director Conor Malone. “We can go wherever there is dark fibre, water and power.”

However, Rackable is not disclosing terms of its first Concentro deal, other than to say many tariffs are possible including pay-as-you-go terms where consumption is measured.

Mobile datacentres have been tried in the past but supporters say that today’s densities and pre-packaged offerings offer a new opportunity.

“Drop-and-go datacentres aren’t new but the [ability to] scale was always the thing that caught you,” said Patrick Fogarty, director of datacentre consulting firm Norman Disney & Young. “They’re a real solution for some scenarios. Also, DC power offers a slice of power saving you don’t normally have. It’s not huge but it’s a good thing.”