Microsoft has added two data center location options for its public-cloud services Windows Azure. The company did not say where exactly the two new data centers now supporting the cloud, revealing only that one is in the western US and the other in the east of the country.

In a blog post, Microsoft’s Cameron Rogers wrote that the expanded footprint for the Azure cloud was a response to growing demand. “These new options add to our worldwide presence and significantly expand our US footprint,” he wrote.

The company has already made Azure compute and storage services available at the new locations, planning to have them support SQL Azure in the coming months.

Before West US and East US came online, only two US locations supported Microsoft’s cloud: North Central US and South Central US. Asia and Europe also each have Azure data center options.

In addition to primary data centers, however, Azure is delivered through an extensive Content Delivery Network (CDN), which consists of eight nodes in eight US locations, eight nodes in the Europe and eight more spread across Asia-Pacific, Qatar and Brazil.

The cloud is supported by Microsoft’s custom-designed servers, optimized for homogeneous applications.

The scale-out servers are small in size, stripped down as much as possible. A typical rack in a Microsoft data center will hold up to 96 of them within the space of 48 standard rack units and two-four top-of-rack switches.

The servers are made of high-efficiency components, use low-power processors and operate in high-temperature environments.

Much of the Azure infrastructure lives in Microsoft’s modular data centers. These facilities are designed to add capacity quickly by installing pre-manufactured modules called ITPACs.