A company is migrating an on-premises web application to AWS. The web application runs on a single server and stores session data in memory. On AWS the company plan to implement multiple Amazon EC2 instances behind an Elastic Load Balancer (ELB). The company want to refactor the application so that data is resilient if an instance fails and user downtime is minimized. Where should the company move session data to MOST effectively reduce downtime and make users’ session data more fault tolerant?