Explanation: In Amazon Web Service, the user can achieve HA by deploying instances in multiple zones. The elasticIP helps the user achieve HA when one of the instances is down but still keeps the same URL. TheAMI helps launching the new instance. The PIOPS is for the performance of EBS and does not help forHA. Reference: http://media.amazonwebservices.com/AWS_Web_Hosting_Best_Practices.pdf