- [Morgan] Time for the next topic under this domain, select high-performing and scalable storage solutions for a workload. When you're building solutions on AWS, you are most likely going to need to figure out how and where to store the data you will be working with. This can seem like a straightforward task, but there are many different AWS storage services that can potentially meet your needs, and being able to choose the right one takes practice. Picking the right storage solution includes evaluating how a solution scales, and how it performs under a given use case. For example, Amazon EBS has totally different scaling mechanisms and performance implications than storage solutions like Amazon S3 or Amazon EFS. Let's say you are hosting a web application on an Amazon EC2 instance using Amazon EBS as the storage for a file system. When the EBS volumes begin to run out of storage capacity, you need to scale the volumes. How do you do this? Well, you need to change the volume size, which is not something that happens automatically. Instead, you must take action for this vertical scaling to take place. This action can, of course, be automated, but adding more memory as the volume needs it isn't something built into the functionality of the service. Let's now compare that to using Amazon EFS. If you were hosting a file system on Amazon EFS, and you anticipate that you will need to vertically scale the storage at one time or another, how can you scale that storage? Is it a task that you need to carry out, as is the case with Amazon EBS? Well, in this case, Amazon EFS will grow and shrink automatically as you add or remove files from the file system. This type of service knowledge can be useful if you were to get questions on the exam that asks you to pick a storage solution with the least amount of operational support needed for storage scaling. You also should be able to determine which storage solution is the best fit based on future storage needs. Data generally isn't static. As you operate your applications over time, data most likely will accumulate, and the rate of that data accumulation should be considered when making architectural decisions. Consider you have an application that needs 3 TB of data storage today, but over the next 5 years, will grow into needing 100 TB of data storage. This is something you would need to think about when choosing a solution. This also means you should know the general upper bounds for capacity for storage solutions. This will help you choose the right service for your future data-storage needs. Beyond comparing AWS storage solutions on scalability, you also should be able to determine which solution would be the most appropriate for a situation based on performance. For example, let's say you have an application that is processing data, and this application needs extremely low latency for reading the data. Based on this vague scenario, you should be thinking about which AWS storage services are best fits for low-latency requirements. Amazon EBS volumes are extremely low latency, but the degree to how performant they can be is configurable. You should be familiar with the different types of EBS volumes, and how performant each type is based on the use case and IOPS. Choosing the correct configurations for EBS volumes can greatly impact performance, so being aware of these configurations is important when architecting solutions. There are many other configurations for storage services that could impact performance, and you should be familiar with the major performance configurations for each service. For example, when designing solutions with Amazon S3, you may be asked to consider how you could improve the performance of data uploads or data retrieval. For data uploads or transfer, you should be familiar with what the basic API calls or CLI commands are for Amazon S3, as well as familiarize yourself with using multipart uploads. Then there are also features like Amazon S3 Accelerator for more performant uploads, or caching with Amazon CloudFront to make data retrieval faster, which can help you make design decisions and answer exam questions. To wrap this up from a broad perspective, you should be focusing on the following when you are studying. Being able to determine which storage services to use that can scale to accommodate current and future storage needs, and choosing AWS services and configurations that meet performance needs under different circumstances. I would recommend really diving into the AWS documentation and whitepapers to learn more about these subjects.