Our hearts go out to those who have suffered through the recent events in Japan. I was relieved to hear from my friends and colleagues there in the days following the earthquake. I'm very impressed by the work that the Japan AWS User Group (JAWS) has done to help some of the companies, schools, and government organizations affected by the disaster to rebuild their IT infrastructure.
We launched our Tokyo Region with a single Availability Zone ("AZ") about a month ago. At that time we said we would be launching a second Tokyo AZ soon. After a very thorough review of our primary and backup power supplies, we have decided to open up that second Availability Zone, effective today.
As you may know, AWS is currently supported in five separate Regions around the world: US East (Northern Virginia), US West (Northern California), EU (Ireland), Asia Pacific (Singapore), and Asia Pacific (Tokyo). Each Region is home to one or more Availability Zones. Each Availability Zone in a Region is engineered to be operationally independent of the other Zones, with independent power, cooling, physical security, and network connectivity. As a developer or system architect, you have full control over the Regions and Availability Zones that your application uses.
A number of our customers are already up and running in Tokyo and have encouraged us to open up the second Availability Zone so that they can add fault tolerance by running in more than one AZ. For example, with the opening of the second AZ developers can use the Amazon Relational Database Service (RDS) in Multi-AZ mode (see my blog post for more information about this), or load balance between web servers running Amazon EC2 in both AZ's.
PS - We continue to monitor the power situation closely. The AWS Service Health Dashboard is the best place to go for information on any possible service issues.