AWS Cloud Data Center in South Korea

Amazon Web Services (AWS), the online retail giant’s cloud-computing division, is adding another cluster of massive data centers to its arsenal, this time in South Korea.

The data centers, which Amazon calls “regions,” are huge investments that help separate AWS from would-be rivals that don’t have as many customers and may not be able to justify the cost of building them.

Amazon has never shared the cost, but analysts believe regions, which include several data centers spread across a city, can run into the hundreds of millions of dollars.

In a blog post Wednesday afternoon, AWS Chief Evangelist Jeff Barr announced the new Korea region, noting that AWS customers there have pushed the company to give them a local option to store data.

Amazon pioneered the business of renting data storage and computer-server time to startups, corporations and government agencies to run their core business processes. It is far and away the leader in providing infrastructure technology over the Web, while Microsoft, Google and others are playing catch up. Building more regions makes that chase harder for rivals.

Barr wrote that the Korea region will open early next year, the fifth in the Asia Pacific area. It will bring the number of AWS regions worldwide to 12, not including regions the company has announced in Ohio and India.