Auto Scaling – Study what services in AWS can be auto-scaled, what triggers scaling, and how auto scaling increases/decreases the number of instances. Elastic Block Store – As the primary storage solution of EC2, study on the types of EBS volumes available. Also study how to secure, backup and restore EBS volumes. S3 / Glacier – AWS offers many types of S3 storage depending on your needs. Study what these types are and what differs between them. Also review on the capabilities of S3 such as hosting a static website, securing access to objects using policies, lifecycle policies, etc. Learn as much about S3 as you can. Storage Gateway – There are occasional questions about Storage Gateway in the exam. You should understand when and which type of Storage Gateway should be used compared to using services like S3 or EBS. You should also know the use cases and differences between DataSync and Storage Gateway. EFS – EFS is a service highly associated with EC2, much like EBS. Understand when to use EFS, compared to using S3, EBS or instance store.