Basically, I'm trying to figure out what design to use. I'm collecting 1TB of data per month using an EC2 instance mounted to EBS. I created another Elastic Beanstalk instance serving as the website, and I wanted to figure out if it's better to access this EC2 instance's data through EFS or S3. Also, the amount of data that the elastic beanstalk webpage would access maybe be 10 - 50GB occasionally from a web application.
Basically, it depends upon the type of data you want to store.
EFS - Amazon EFS is automatically scalable - that means that your running applications won't have any problems if the workload suddenly becomes higher - the storage will scale itself automatically. If the workload decreases - the storage will scale down, so you won't pay anything for the storage you don't use. Good for shareable applications and workloads , Faster than S3
S3 - Amazon S3 also allows hosting static website content. provides simple object storage, useful for hosting website images and videos, data analytics, and both mobile and web applications. Object storage manages data as objects, meaning all data types are stored in their native formats.
So I would suggest, as you are collecting 1TB of data and webpage would access 10 - 50GB occasionally, so S3 will make your process (API's) slow and its good the amount of disk space you use, have to pay for that only.
And as you are talking about 1Tb, if data goes beyond that, the disk will be scalable and the application will be highly available.