In the high availability and scaling section of the exam, you can expect questions that will test how well you understand the AWS architecture and how to make sure that the services are highly available and scalable within the scope of AWS. Make sure not to forget that some services are highly available and/or scalable by default, while some will take some architecting to achieve that. There are several crucial aspects about high availability and scaling that you should remember: 

• Make sure you understand high availability across availability zones and regions.
• Understand what can impact the availability for an availability zone or a region.
• Make sure you know how to make a VPC and its components highly available.
• Understand the high availability and scaling of EC2 and RDS instances.
• Familiarize yourself with the SLA, that is, the availability and scaling of managed services in AWS.
• Explore the AWS disaster recovery scenarios.
• Understand how to use ELB, Autoscaling, CloudWatch, and Route 53 for high availability.