The most useful first distinction among Amazon S3, EBS, and EFS is how the application accesses the data. Object storage, block storage, and a shared file system solve different needs. The phrase “store files” alone is too broad to select one reliably.
Match these original requirements
A company needs to store product images as objects and retrieve them through service requests. The application does not require a mounted shared file system. Amazon S3 is the direct match to the object-storage requirement.
A team needs persistent block storage for an EC2 workload that expects disk-like volumes. Amazon EBS fits the block-storage description. Avoid interpreting this as a rule that every EBS volume can be attached in every possible way; attachment features and constraints depend on the volume and instance setup.
A Linux application running on multiple instances needs concurrent access to shared files through NFS. Amazon EFS matches that shared file-system requirement.
Use the AWS Cloud Practitioner storage review as a compact reference after identifying which access model each question describes. Learning the category first reduces dependence on a service acronym appearing in the question.
Eliminate the attractive distractor
Suppose a question asks for a shared NFS file system, but an answer explanation chooses S3 because it is durable. Durability is relevant to storage, yet it does not satisfy the NFS requirement. An option can offer a desirable property and still fail the decisive part of the prompt.
Likewise, selecting EBS solely because an application runs on EC2 ignores the rest of the architecture. EC2 applications can use different storage services; the required interface and sharing behavior matter.
AWS’s storage overview groups the services and explains their main purposes. For foundational exam review, you usually gain more from understanding those categories than from memorizing an isolated maximum-capacity number.
A short self-test
Write these three clues without service names: objects accessed through APIs; block volume for a virtual machine; shared NFS file system. Match each clue, then explain why the two alternatives are less suitable.
Next, alter one clue. Change “shared NFS” to “object-based application uploads.” If you keep the same answer without reconsidering the requirement, you are remembering the story instead of solving the storage problem.
Continue mixed review with the Cloud Practitioner sample questions. Track whether a missed storage question came from confusing interfaces, overlooking sharing, or using cost as a shortcut without enough information. Those are different mistakes and call for different follow-up notes.