S3 Files is a newly released feature of S3 that provides a file system on top of your bucket powered by EFS. For reads, the data is loaded into EFS when an object is less than 128KB, by default, for objects equal to or larger than the threshold S3 Files prefers streaming the data directly from the bucket. While writing files, EFS is used and any changes are synched automaticaly with the underlying S3 bucket.
No matter how you decide to dress object storage and treat it like a file system it can always come to bite you, if you're not careful. Here's how renames and moves are handled:
Read from linkAmazon S3 uses a flat storage structure where objects are identified by their key names. While S3 Files lets you organize your data in directories, S3 has no native concept of directories. What appears as a directory in your file system is a common prefix shared by the keys of the objects within the S3 bucket. Additionally, S3 objects are immutable and do not support atomic renames. As a result, when you rename or move a file, S3 Files must write the data to a new object with the updated key and delete the original. When you rename or move a directory, S3 Files must repeat this process for every object that shares that prefix. Therefore, when you rename or move a directory containing tens of millions of files, your S3 request costs and the synchronization time increase significantly.