Contest

A popular e-commerce website needs to support one million transactions per hour for normal operation. You can assume a standard configuration of firewall, load balancer, web tier, app tier and database cluster.

The average duration of each transaction on the application server tier is 900ms. Each application server is CPU bound to 20 simultaneous transactions before experiencing performance degradation. To reduce risk, management has restricted production code deployments to a 30 minute window every two weeks, and it takes four minutes to restart an application server after new code has been deployed to it.

Assuming that you can load balance across two versions of the application at the same time, what would be the minimum number of application servers and optimal deployment strategy to guarantee four 9s at normal operation?

Submit your answer below. The winner will receive a trip to an upcoming Gartner summit.